Sample records for maximum power generated

The development studies in thermoelectric generator (TEG) systems are mostly disconnected to parametric optimization of the module components. In this study, optimum footprint ratio of n- and p-type thermoelectric (TE) elements is explored to achieve maximumpowergeneration, maximum cost......-performance, and variation of efficiency in the uni-couple over a wide range of the heat transfer coefficient on the cold junction. The three-dimensional (3D) governing equations of the thermoelectricity and the heat transfer are solved using the finite element method (FEM) for temperature dependent properties of TE...... materials. The results, which are in good agreement with the previous computational studies, show that the maximumpowergeneration and the maximum cost-performance in the module occur at An/Ap

Highlights: • A MaximumPower Point Tracking (MPPT) method for thermoelectric generators is proposed. • A power converter is controlled to operate on a pre-programmed locus. • The proposed MPPT technique has the advantage of operational and design simplicity. • The experimental average deviation from the MPP power of the TEG source is 1.87%. - Abstract: ThermoElectric Generators (TEGs) are capable to harvest the ambient thermal energy for power-supplying sensors, actuators, biomedical devices etc. in the μW up to several hundreds of Watts range. In this paper, a MaximumPower Point Tracking (MPPT) method for TEG elements is proposed, which is based on controlling a power converter such that it operates on a pre-programmed locus of operating points close to the MPPs of the power–voltage curves of the TEG power source. Compared to the past-proposed MPPT methods for TEGs, the technique presented in this paper has the advantage of operational and design simplicity. Thus, its implementation using off-the-shelf microelectronic components with low-power consumption characteristics is enabled, without being required to employ specialized integrated circuits or signal processing units of high development cost. Experimental results are presented, which demonstrate that for MPP power levels of the TEG source in the range of 1–17 mW, the average deviation of the power produced by the proposed system from the MPP power of the TEG source is 1.87%.

The present study focuses on the thermoelectric generator (TEG) using loop heat pipe (LHP) and design match for maximum-powergeneration. The TEG uses loop heat pipe, a passive cooling device, to dissipate heat without consuming power and free of noise. The experiments for a TEG with 4W rated power show that the LHP performs very well with overall thermal resistance 0.35 K W-1, from the cold side of TEG module to the ambient. The LHP is able to dissipate heat up to 110W and is maintenance free. The TEG design match for maximum-powergeneration, called “near maximum-power point operation (nMPPO)”, is studied to eliminate the MPPT (maximum-power point tracking controller). nMPPO is simply a system design which properly matches the output voltage of TEG with the battery. It is experimentally shown that TEG using design match for maximum-powergeneration (nMPPO) performs better than TEG with MPPT.

Highlights: • To analyze the benefit of applying a new control strategy to maximise energy yield. • To operate some wind turbines at non-optimum points for reducing wake effects. • Single, partial and multiple wakes for any wind direction are taken into account. • Thrust coefficient is computed according to Blade Element Momentum (BEM) theory. - Abstract: This paper analyses, from a steady state point of view, the potential benefit of a Wind Power Plant (WPP) control strategy whose main objective is to maximise its total energy yield over its lifetime by taking into consideration that the wake effect within the WPP varies depending on the operation of each wind turbine. Unlike the conventional approach in which each wind turbine operation is optimised individually to maximise its own energy capture, the proposed control strategy aims to optimise the whole system by operating some wind turbines at sub-optimum points, so that the wake effect within the WPP is reduced and therefore the total powergeneration is maximised. The methodology used to assess the performance of both control approaches is presented and applied to two particular study cases. It contains a comprehensive wake model considering single, partial and multiple wake effects among turbines. The study also takes into account the Blade Element Momentum (BEM) theory to accurately compute both power and thrust coefficient of each wind turbine. The results suggest a good potential of the proposed concept, since an increase in the annual energy captured by the WPP from 1.86% up to 6.24% may be achieved (depending on the wind rose at the WPP location) by operating some specific wind turbines slightly away from their optimum point and reducing thus the wake effect

The present study proposes a PV system design, called 'near-maximumpower-point-operation' (nMPPO) that can maintain the performance very close to PV system with MPPT (maximum-power-point tracking) but eliminate hardware of the MPPT. The concept of nMPPO is to match the design of battery bank voltage V{sub set} with the MPP (maximum-power point) of the PV module based on an analysis using meteorological data. Three design methods are used in the present study to determine the optimal V{sub set}. The analytical results show that nMPPO is feasible and the optimal V{sub set} falls in the range 13.2-15.0V for MSX60 PV module. The long-term performance simulation shows that the overall nMPPO efficiency {eta}{sub nMPPO} is higher than 94%. Two outdoor field tests were carried out in the present study to verify the design of nMPPO. The test results for a single PV module (60Wp) indicate that the nMPPO efficiency {eta}{sub nMPPO} is mostly higher than 93% at various PV temperature T{sub pv}. Another long-term field test of 1kWp PV array using nMPPO shows that the powergeneration using nMPPO is almost identical with MPPT at various weather conditions and T{sub pv} variation from 24{sup o}C to 70{sup o}C. (author)

Highlights: • A novel algorithm for a single-axis sun tracker is developed to increase the efficiency. • Photovoltaic module is rotated to find the optimal angle for generating the maximumpower. • Electric energy increases up to 8.3%, compared with that of the tracker with three fixed angles. • The rotation range is optimized to reduce energy consumption from the rotation operations. - Abstract: The purpose of this study is to develop a novel algorithm for a single-axis maximumpowergeneration sun tracker in order to identify the optimal stopping angle for generating the maximum amount of daily electric energy. First, the photovoltaic modules of the single-axis maximumpowergeneration sun tracker are automatically rotated from 50° east to 50° west. During the rotation, the instantaneous powergenerated at different angles is recorded and compared, meaning that the optimal angle for generating the maximumpower can be determined. Once the rotation (detection) is completed, the photovoltaic modules are then rotated to the resulting angle for generating the maximumpower. The photovoltaic module is rotated once per hour in an attempt to detect the maximum irradiation and overcome the impact of environmental effects such as shading from cloud cover, other photovoltaic modules and surrounding buildings. Furthermore, the detection range is halved so as to reduce the energy consumption from the rotation operations and to improve the reliability of the sun tracker. The results indicate that electric energy production is increased by 3.4% in spring and autumn, 5.4% in summer, and 8.3% in winter, compared with that of the same sun tracker with three fixed angles of 50° east in the morning, 0° at noon and 50° west in the afternoon.

The magnetism attraction between permanent magnets and soft ironcore lamination in a conventional electric ironcore generator is often known as cogging. Cogging requires an additional input power to overcome, hence became one of the power loss sources. With the increasing of power output, the cogging is also proportionally increased. This leads to the increasing of the supplied power of the driver motor to overcome the cog. Therefore, this research is embarked to study fundamentally about the possibility of removing ironcore lamination in an electric generator to see its performance characteristic. In the maximumpower point tracking test, the fabricated ironless coreless electricity generator was tested by applying the load on the ironless coreless electricity generator optimization to maximize the powergenerated, voltage and the current produced by the ironless coreless electricity generator when the rotational speed of the rotor increased throughout the test. The rotational torque and power output are measured, and efficiency is then analyzed. Results indicated that the generator produced RMS voltage of 200VAC at rotational speed of 318 RPM. Torque required to rotate the generator was at 10.8Nm. The generator had working efficiency of 77.73% and the powergenerated was at 280W.

Thermo Electric Generator (TEG) modules are often connected in a series and/or parallel system in order to match the TEG system voltage with the load voltage. However, in order to be able to control the power production of the TEG system a DC/DC converter is inserted between the TEG system...... and the load. The DC/DC converter is under the control of a MaximumPower Point Tracker (MPPT) which insures that the TEG system produces the maximum possible power to the load. However, if the conditions, e.g. temperature, health, etc., of the TEG modules are different each TEG module will not produce its...

To make full use of the maximum output power of automobile exhaust thermoelectric generator (AETEG) based on Bi2Te3 thermoelectric modules (TEMs), taking into account the advantages and disadvantages of existing maximumpower point tracking methods, and according to the output characteristics of TEMs, a hybrid maximumpower point tracking method combining perturb and observe (P&O) algorithm, quadratic interpolation and constant voltage tracking method was put forward in this paper. Firstly, it searched the maximumpower point with P&O algorithms and a quadratic interpolation method, then, it forced the AETEG to work at its maximumpower point with constant voltage tracking. A synchronous buck converter and controller were implemented in the electric bus of the AETEG applied in a military sports utility vehicle, and the whole system was modeled and simulated with a MATLAB/Simulink environment. Simulation results demonstrate that the maximum output power of the AETEG based on the proposed hybrid method is increased by about 3.0% and 3.7% compared with that using only the P&O algorithm and the quadratic interpolation method, respectively. The shorter tracking time is only 1.4 s, which is reduced by half compared with that of the P&O algorithm and quadratic interpolation method, respectively. The experimental results demonstrate that the tracked maximumpower is approximately equal to the real value using the proposed hybrid method,and it can preferentially deal with the voltage fluctuation of the AETEG with only P&O algorithm, and resolve the issue that its working point can barely be adjusted only with constant voltage tracking when the operation conditions change.

The article studies the dynamic performance of a family of maximumpower point tracking circuits used for photovoltaic generation. It revisits the sinusoidal extremum seeking control (ESC) technique which can be considered as a particular subgroup of the Perturb and Observe algorithms. The sinusoidal ESC technique consists of adding a small sinusoidal disturbance to the input and processing the perturbed output to drive the operating point at its maximum. The output processing involves a synchronous multiplication and a filtering stage. The filter instance determines the dynamic performance of the MPPT based on sinusoidal ESC principle. The approach uses the well-known root-locus method to give insight about damping degree and settlement time of maximum-seeking waveforms. This article shows the transient waveforms in three different filter instances to illustrate the approach. Finally, an experimental prototype corroborates the dynamic analysis.

A well engineered renewable remote energy system, utilizing the principal of MaximumPower Point Tracking can be m ore cost effective, has a higher reliability and can improve the quality of life in remote areas. This paper reports that a high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximumpower point of the input source under varying input and output parameters. Maximumpower point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of 15% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply systems. The advantages at larger temperature variations and larger power rated systems are much higher. Other advantages include optimal sizing and system monitor and control

Full Text Available This study proposes and implements maximumpower Point Tracking (MPPT control on thermoelectric generation system using an extremum seeking control (ESC algorithm. The MPPT is applied to guarantee maximumpower extraction from the TEG system. The work has been carried out through modelling of thermoelectric generator/dc-dc converter system using Matlab/Simulink. The effectiveness of ESC technique has been assessed by comparing the results with those of the Perturb and Observe (P&O MPPT method under the same operating conditions. Results indicate that ESC MPPT method extracts more power than the P&O technique, where the output power of ESC technique is higher than that of P&O by 0.47 W or 6.1% at a hot side temperature of 200 °C. It is also noted that the ESC MPPT based model is almost fourfold faster than the P&O method. This is attributed to smaller MPPT circuit of ESC compared to that of P&O, hence we conclude that the ESC MPPT method outperforms the P&O technique.

In the frame of this thesis, a new experimental setup for the measurement of the energy loss of carbon ions at maximum stopping power in a hot laser-generated plasma has been developed and successfully tested. In this parameter range where the projectile velocity is of the same order of magnitude as the thermal velocity of the plasma free electrons, large uncertainties of up to 50% are present in the stopping-power description. To date, no experimental data are available to perform a theory benchmarking. Testing the different stopping theories is yet essential for inertial confinement fusion and in particular for the understanding of the alpha-particle heating of the thermonuclear fuel. Here, for the first time, precise measurements were carried out in a reproducible and entirely characterized beam-plasma configuration. It involved a nearly fully-stripped ion beam probing a homogeneous fully-ionized plasma. This plasma was generated by irradiating a thin carbon foil with two high-energy laser beams and features a maximum electron temperature of 200 eV. The plasma conditions were simulated with a two-dimensional radiative hydrodynamic code, while the ion-beam charge-state distribution was predicted by means of a Monte-Carlo code describing the charge-exchange processes of projectile ions in plasma. To probe at maximum stopping power, high-frequency pulsed ion bunches were decelerated to an energy of 0.5 MeV per nucleon. The ion energy loss was determined by a time-of-flight measurement using a specifically developed chemical-vapor-deposition diamond detector that was screened against any plasma radiation. A first experimental campaign was carried out using this newly developed platform, in which a precision better than 200 keV on the energy loss was reached. This allowed, via the knowledge of the plasma and of the beam parameters, to reliably test several stopping theories, either based on perturbation theory or on a nonlinear T-Matrix formalism. A preliminary

of noise. The experiments for a TEG with 4W rated power show that the LHP performs very well with overall thermal resistance 0.35 K W-1, from the cold side of TEG module to the ambient. The LHP is able to dissipate heat up to 110W and is maintenance free

Photovoltaic (PV) powergenerators can be used for converting the energy of solar radiation directly into electrical energy without any moving parts. The operation of the generators is highly affected by operating conditions, most importantly irradiances and temperatures of PV cells. PV powergenerators are prone to electrical losses if the operating conditions are non-uniform such as in a case where part of the modules of a generator are shaded while the rest are receiving the global solar radiation. These conditions are called partial shading conditions and they have been recognized as a major cause of energy losses in PV powergenerators. In this thesis, the operation of silicon-based PV powergenerators under partial shading conditions is studied using Matlab Simulink simulation model. The operation of the model has been verified by measurements of electrical characteristics of a PV module under several different operating conditions and also under partial shading conditions. A systematic approach to study the effects of partial shading conditions has been developed and used. In addition to the systematic approach, a vast amount of data measured from the Tampere University of Technology (TUT) Solar Photovoltaic Power Station Research Plant are analyzed and used as input for the simulation model to study operation of PV powergenerators under actual operating conditions. Partial shading conditions have severe effects on the electrical characteristics of PV powergenerators and can cause multiple maximumpower points (MPPs) to the power-voltage curve of the generators. In most cases, partial shading conditions lead to the occurrence of multiple MPPs, but also only one MPP can be present despite of partial shading. Reasons for this phenomenon are presented and analyzed in this thesis. Because of multiple MPPs, a considerable amount of available electrical energy may be lost when the generator is operating at a local MPP with low power instead of the global MPP. In

Highlights: ► This paper presents MPPT based control for optimal wind energy capture using RBFN. ► MPSO is adopted to adjust the learning rates to improve the learning capability. ► This technique can maintain the system stability and reach the desired performance. ► The EMF in the rotating reference frame is utilized in order to estimate speed. - Abstract: This paper presents maximum-power-point-tracking (MPPT) based control algorithms for optimal wind energy capture using radial basis function network (RBFN) and a proposed torque observer MPPT algorithm. The design of a high-performance on-line training RBFN using back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller for the sensorless control of a permanent magnet synchronous generator (PMSG). The MPSO is adopted in this study to adapt the learning rates in the back-propagation process of the RBFN to improve the learning capability. The PMSG is controlled by the loss-minimization control with MPPT below the base speed, which corresponds to low and high wind speed, and the maximum energy can be captured from the wind. Then the observed disturbance torque is feed-forward to increase the robustness of the PMSG system

The present study was carried out in order to track the maximumpower point in a variable speed turbine by minimizing electromechanical torque changes using a sliding mode control strategy.In this strategy,fhst,the rotor speed is set at an optimal point for different wind speeds.As a result of which,the tip speed ratio reaches an optimal point,mechanical power coefficient is maximized,and wind turbine produces its maximumpower and mechanical torque.Then,the maximum mechanical torque is tracked using electromechanical torque.In this technique,tracking error integral of maximum mechanical torque,the error,and the derivative of error are used as state variables.During changes in wind speed,sliding mode control is designed to absorb the maximum energy from the wind and minimize the response time of maximumpower point tracking (MPPT).In this method,the actual control input signal is formed from a second order integral operation of the original sliding mode control input signal.The result of the second order integral in this model includes control signal integrity,full chattering attenuation,and prevention from large fluctuations in the powergenerator output.The simulation results,calculated by using MATLAB/m-file software,have shown the effectiveness of the proposed control strategy for wind energy systems based on the permanent magnet synchronous generator (PMSG).

Highlights: • Charges with direct and MPPT conditions have been compared. • Perturb and observation method has been practically tested on a new TEG. • Matched load condition has been experimentally investigated. • To increase the efficiency of a TEG, the charge with MPPT should be used. • The charge with MPPT provides twice-fold increase in efficiency. - Abstract: Thermoelectric generators (TEGs) directly generate electrical power from the geothermal/waste heat as well as contribute to efficient usage of the energy. TEGs cannot be operated at full capacity without additional electronic equipments, since the internal resistances of TEGs are not equal to the device resistances connected across TEGs. For this reason, in this paper, the application of a DC–DC boost converter with maximumpower point tracking (MPPT) based on microcontroller embedded in perturb and observe (P&O) algorithm has been proposed to obtain maximumpower from a newly designed portable TEG (pTEG) in a real TEG system. The matched condition load for the pTEG has been experimentally investigated. Firstly, the pTEG has been directly charged to the battery pack, secondly it has been charged through the improved convertor with MPPT. In the first one, the pTEG operated with less efficiency than half of its full capacity, whereas, in the second, the pTEG operated efficiency near its full capacity

This paper discusses a new control strategy for photovoltaic powergeneration systems with consideration of dynamic characteristics of the photovoltaic cells. The controller estimates internal currents of an equivalent circuit for the cells. This estimated, or the virtual current and the actual voltage of the cells are fed to a conventional Maximum-Power-Point-Tracking (MPPT) controller. Consequently, this MPPT controller still tracks the optimum point even though it is so designed that the seeking speed of the operating point is extremely high. This system may suit for applications, which are installed in rapidly changeable insolation and temperature-conditions e.g. automobiles, trains, and airplanes. The proposed method is verified by experiment with a combination of this estimating function and the modified Boehringer's MPPT algorithm.

A hybrid power control system is proposed in the paper, consisting of solar power, wind power, and a diesel-engine. To achieve a fast and stable response for the real power control, an intelligent controller was proposed, which consists of the Wilcoxon (radial basis function network) RBFN and the improved (Elman neural network) ENN for (maximumpower point tracking) MPPT. The pitch angle control of wind power uses improved ENN controller, and the output is fed to the wind turbine to achieve the MPPT. The solar array is integrated with an RBFN control algorithm to track the maximumpower. MATLAB (MATrix LABoratory)/Simulink was used to build the dynamic model and simulate the solar and diesel-wind hybrid power system. - Highlights: ► To achieve a fast and stable response for the real power control. ► The pitch control of wind power uses improved ENN (Elman neural network) controller to achieve the MPPT (maximumpower point tracking). ► The RBFN (radial basis function network) can quickly and accurately track the maximumpower output for PV (photovoltaic) array. ► MATLAB was used to build the dynamic model and simulate the hybrid power system. ► This method can reach the desired performance even under different load conditions

Full Text Available The power extracted from PV arrays is usually maximized using maximumpower point tracking algorithms. One of the most widely used techniques is the perturb & observe algorithm, which periodically perturbs the operating point of the PV array, sometime with an adaptive perturbation step, and compares the PV power before and after the perturbation. This paper analyses the most suitable perturbation step to optimize maximumpower point tracking performance and suggests a design criterion to select the parameters of the controller. Using this proposed adaptive step, the MPPT perturb & observe algorithm achieves an excellent dynamic response by adapting the perturbation step to the actual operating conditions of the PV array. The proposed algorithm has been validated and tested in a laboratory using a dual input inductor push-pull converter. This particular converter topology is an efficient interface to boost the low voltage of PV arrays and effectively control the power flow when input or output voltages are variable. The experimental results have proved the superiority of the proposed algorithm in comparison of traditional perturb & observe and incremental conductance techniques.

To achieve maximumpower point tracking (MPPT) for wind powergeneration systems, the rotational speed of wind turbines should be adjusted in real time according to wind speed. In this paper, a Wilcoxon radial basis function network (WRBFN) with hill-climb searching (HCS) MPPT strategy is proposed for a permanent magnet synchronous generator (PMSG) with a variable-speed wind turbine. A high-performance online training WRBFN using a back-propagation learning algorithm with modified particle swarm optimization (MPSO) regulating controller is designed for a PMSG. The MPSO is adopted in this study to adapt to the learning rates in the back-propagation process of the WRBFN to improve the learning capability. The MPPT strategy locates the system operation points along the maximumpower curves based on the dc-link voltage of the inverter, thus avoiding the generator speed detection. (author)

to fatigue damage have been identified. In these regions, the turbine energy output can be increased by deflecting the trailing edge (TE) flap in order to track the maximumpower coefficient as a function of local, instantaneous speed ratios. For this purpose, the TE flap configuration for maximumpower...... generation has been using blade element momentum theory. As a first step, the operation in non-uniform wind field conditions was analysed. Firstly, the deterministic fluctuation in local tip speed ratio due to wind shear was evaluated. The second effect is associated with time delays in adapting the rotor...

Historically, the electric utility demand in most countries has increased rapidly, with a doubling of approximately 10 years in the case of developing countries. In order to meet this growth in demand, the planners of expansion policies were concerned with obtaining expansion pans which dictate what new generation facilities to add and when to add them. This paper reports that, however, the practical planning problem is extremely difficult and complex, and required many hours of the planner's time even though the alternatives examined were extremely limited. In this connection, increased motivation for more sophisticated techniques of valuating utility expansion policies has been developed during the past decade. Among them, the long-range generation expansion planning is to select the most economical and reliable generation expansion plans in order to meet future power demand over a long period of time subject to a multitude of technical, economical, and social constraints

The paper deals with the evaluation of powergenerated by variable and constant frequency offshore wind farms connected to a single large power converter. A methodology to analyze different wind speed scenarios and system electrical frequencies is presented and applied to a case study, where it is shown that the variable frequency wind farm concept (VF) with a single power converter obtains 92% of the total available power, obtained with individual power converters in each wind turbine (PC). The PC scheme needs multiple power converters implying drawbacks in terms of cost, maintenance and reliability. The VF scheme is also compared to a constant frequency scheme CF, and it is shown that a significant power increase of more than 20% can be obtained with VF. The case study considers a wind farm composed of four wind turbines based on synchronous generators. (author)

Pyroelectric thermal-to-electric energy conversion is accomplished by a cyclic process of thermally-inducing polarization changes in the material under an applied electric field. The pyroelectric MEMS device investigated consisted of a thin film PZT capacitor with platinum bottom and iridium oxide top electrodes. Electric fields between 1-20 kV/cm with a 30% duty cycle and frequencies from 0.1 - 100 Hz were tested with a modulated continuous wave IR laser with a duty cycle of 20% creating temperature swings from 0.15 - 26 °C on the pyroelectric receiver. The net output power of the device was highly sensitive to the phase delay between the laser power and the applied electric field. A thermal model was developed to predict and explain the power loss associated with finite charge and discharge times. Excellent agreement was achieved between the theoretical model and the experiment results for the measured power density versus phase delay. Limitations on the charging and discharging rates result in reduced power and lower efficiency due to a reduced net work per cycle. (paper)

The charging for a service is a supplier's remuneration for the expenses incurred in providing it. There are currently two charges for electricity: consumption and maximum demand. While no problem arises about the former, the issue is more complicated for the latter and the analysis in this article tends to show that the annual charge for maximum demand arbitrarily discriminates among consumer groups, to the disadvantage of some [it

According to the International Energy Agency, 1.4 billion people are without electricity in the poorest countries and 2.5 billion people rely on biomass to meet their energy needs for cooking in developing countries. The use of cooking stoves equipped with small thermoelectric generator to provide electricity for basic needs (LED, cell phone and radio charging device) is probably a solution for houses far from the power grid. The cost of connecting every house with a landline is a lot higher than dropping thermoelectric generator in each house. Thermoelectric generators have very low efficiency but for isolated houses, they might become really competitive. Our laboratory works in collaboration with plane`te-bois (a non governmental organization) which has developed energy-efficient multifunction (cooking and hot water) stoves based on traditional stoves designs. A prototype of a thermoelectric generator (Bismuth Telluride) has been designed to convert a small part of the energy heating the sanitary water into electricity. This generator can produce up to 10 watts on an adapted load. Storing this energy in a battery is necessary as the cooking stove only works a few hours each day. As the working point of the stove varies a lot during the use it is also necessary to regulate the electrical power. An electric DC DC converter has been developed with a maximumpower point tracker (MPPT) in order to have a good efficiency of the electronic part of the thermoelectric generator. The theoretical efficiency of the MMPT converter is discussed. First results obtained with a hot gas generator simulating the exhaust of the combustion chamber of a cooking stove are presented in the paper.

In piezoelectric energy harvesting (PEH) systems, energy extracted from piezoelectric structure can be increased by making piezoelectric voltage in phase with vibration velocity and raising the voltage amplitude. Such voltage manipulations can be realized by synchronously flipping the piezoelectric voltage with respect to a bias dc source at every displacement extremum. Given that net harvested energy is obtained by deducting dissipated energy from total extracted energy, a sophisticated voltage bias-flipping scheme, which can maximize extracted energy at low dissipative cost, is required towards harvested energy optimization. This paper extends the state of the art by proposing the best bias-flip strategy, which is delivered on conceptual synchronized multiple bias-flip (SMBF) interface circuits. The proposed strategy coordinates both requirements on larger voltage change in synchronized instant for more extracted energy and smaller voltage change in each bias-flip action for less dissipated energy. It not only leads to further enhancement of harvesting capability beyond existing solutions, but also provides an unprecedented physical insight on maximum achievable harvesting capability of PEH interface circuit

Based on the current models of phosphoric acid fuel cells (PAFCs) and thermoelectric generators (TGs), a new hybrid system is proposed, in which the effects of multi-irreversibilities resulting from the activation, concentration, and ohmic overpotentials in the PAFC, Joule heat and heat leak in the TG, finite-rate heat transfer between the TG and the heat reservoirs, and heat leak from the PAFC to the environment are taken into account. Expressions for the power output and efficiency of the PAFC, TG, and hybrid system are analytically derived and directly used to discuss the performance characteristics of the hybrid system. The optimal relationship between the electric currents in the PAFC and TG is obtained. The maximumpower output is numerically calculated. It is found that the maximumpower output density of the hybrid system will increase about 150 Wm-2, compared with that of a single PAFC. The problem how to optimally match the load resistances of two subsystems is discussed. Some significant results for practical hybrid systems are obtained.

This paper deals with a maximumpower point tracking (MPPT) control of the photovoltaic generation with the single-phase utility interactive inverter. The photovoltaic arrays are connected by employing the PWM current source inverter to the utility. The use of the pulsating dc current and voltage allows the maximumpower point to be searched. The inverter can regulate the array voltage and keep the arrays to the maximumpower. This paper gives the control method and the experimental results.

Nowadays, incentives and financing options for developing renewable energy facilities and the new development in variable speed wind technology make wind energy a competitive source if compared with conventional generation ones. In order to improve the effectiveness of variable speed wind systems, adaptive control systems able to cope with time variances of the system under control are necessary. On these basis, a data driven designing methodology for TSK fuzzy models design is presented in this paper. The methodology, on the basis of given input-output numerical data, generates the 'best' TSK fuzzy model able to estimate with high accuracy the maximum extractable power from a variable speed wind turbine. The design methodology is based on fuzzy clustering methods for partitioning the input-output space combined with genetic algorithms (GA), and recursive least-squares (LS) optimization methods for model parameter adaptation

MPPT control method is similar to hill-climbing used as MPPT control in photovoltaic ...climbing method used as MPPT control in photovoltaic systems. In addition, the proposed MPPT control strategy is generic to all the hydrokinetic...convert AC power from the generator into DC power and a boost converter is used to implement energy flow control . On the load side, an electronic

The maximum credible beam power is defined as the highest credible average beam power that the accelerator can deliver to the point in question, given the laws of physics, the beam line design, and assuming all protection devices have failed. For a new accelerator project, the official maximum credible beam power is determined by project staff in consultation with the Radiation Physics Department, after examining the arguments and evidence presented by the appropriate accelerator physicist(s) and beam line engineers. The definitive parameter becomes part of the project's safety envelope. This technical note will first review the studies that were done for the Gun Test Facility (GTF) at SSRL, where a photoinjector similar to the one proposed for the LCLS is being tested. In Section 3 the maximum charge out of the gun for a single rf pulse is calculated. In Section 4, PARMELA simulations are used to track the beam from the gun to the end of the photoinjector. Finally in Section 5 the beam through the matching section and injected into Linac-1 is discussed

Full Text Available This paper focuses on the modeling of wind turbines equipped with direct drive permanent magnet synchronous generators for fundamental frequency power system simulations. Specifically, a procedure accounting for the system active power losses to initialize the simulation starting from the load flow results is proposed. Moreover, some analytical assessments are detailed on typical control schemes for fully rated wind turbine generators, thereby highlighting how active power losses play a fundamental role in the effectiveness of the wind generator control algorithm. Finally, the paper proposes analytical criteria to design the structure and the parameters of the regulators of the wind generator control scheme. Simulations performed with Digsilent Power Factory validated the proposed procedure, highlighting the impact of active power losses on the characterization of the initial steady state and that the simplifying assumptions done in order to synthesize the controllers are consistent with the complete modeling performed by the aforementioned power system simulator.

In the second half of twentieth century, nuclear power became an industrial reality. Now the operating 433 power plants, the 37 plants under construction, near 9000 years/reactor with only one serious accident with emission of radioactive material to the environment (Chernobyl) show the maturity of this technology. Today nuclear power contribute a 17% to the global generation and an increase of 75 % of the demand of electricity is estimated for 2020 while this demand is expected to triplicate by 2050. How this requirement can be satisfied? All the indicators seems to demonstrate that nuclear power will be the solution because of the shortage of other sources, the increase of the prices of the non renewable fuels and the scarce contribution of the renewable ones. In addition, the climatic changes produced by the greenhouse effect make even more attractive nuclear power. The situation of Argentina is analyzed and compared with other countries. The convenience of an increase of nuclear power contribution to the total national generation seems clear and the conclusion of the construction of the Atucha II nuclear power plant is recommended

In this paper an extension of the spectrum of applicability of rotors with active aerody-namic devices is presented. Besides the classical purpose of load alleviation, a secondary objective is established: power capture optimization. As a _rst step, wind speed regions that contribute little to fa...

Full Text Available Solar energy has become a promising alternative to conventional fossil fuel sources. Solar panels are used to collect solar radiation and convert it into electricity. One of the techniques used to maximize the effectiveness of this energy alternative is to maximize the power output of the solar collector. In this project the maximumpower is calculated by determining the voltage and the current of maximumpower. These quantities are determined by finding the maximum value for the equation for power using differentiation. After the maximum values are found for each time of day, each individual quantity, voltage of maximumpower, current of maximumpower, and maximumpower is plotted as a function of the time of day.

and market segments which are not yet quantified. This paper quantifies a micro-CHP system based on a solid oxide fuel cell (SOFC) and a high-performance TE generator. Based on a 3 kW fuel input, the hybrid SOFC implementation boosts electrical output from 945 W to 1085 W, with 1794 W available for heating...... the electricity production in micro-CHP systems by more than 15%, corresponding to system electrical efficiency increases of some 4 to 5 percentage points. This will make fuel cell-based micro-CHP systems very competitive and profitable and will also open opportunities in a number of other potential business...

Full Text Available Direct current (DC traction power systems are widely used in metro transport systems, with running rails usually being used as return conductors. When traction current flows through the running rails, a potential voltage known as “rail potential” is generated between the rails and ground. Currently, abnormal rises of rail potential exist in many railway lines during the operation of railway systems. Excessively high rail potentials pose a threat to human life and to devices connected to the rails. In this paper, the effect of regenerative power distribution on rail potential is analyzed. Maximum safety regenerative power tracking is proposed for the control of maximum absolute rail potential and energy consumption during the operation of DC traction power systems. The dwell time of multiple trains at each station and the trigger voltage of the regenerative energy absorbing device (READ are optimized based on an improved particle swarm optimization (PSO algorithm to manage the distribution of regenerative power. In this way, the maximum absolute rail potential and energy consumption of DC traction power systems can be reduced. The operation data of Guangzhou Metro Line 2 are used in the simulations, and the results show that the scheme can reduce the maximum absolute rail potential and energy consumption effectively and guarantee the safety in energy saving of DC traction power systems.

The paper describes two different closed-loop control criteria for the maximumpower point tracking of the voltage-current characteristic of a photovoltaic generator. The two criteria are discussed and compared, inter alia, with regard to the setting-up problems that they pose. Although a detailed analysis is not embarked upon, the paper also provides some quantitative information on the energy advantages obtained by using electronic maximumpower point tracking systems, as compared with the situation in which the point of operation of the photovoltaic generator is not controlled at all. Lastly, the paper presents two high-efficiency MPPT converters for experimental photovoltaic plants of the stand-alone and the grid-interconnected type.

Connection of Distributed Generation (DG) units to a distribution network will result in a local voltage increase. As there will be a maximum on the allowable voltage increase, this will limit the maximum allowable penetration level of DG. By reactive power compensation (by the DG unit itself) a

The maximum LOD score statistic is extremely powerful for gene mapping when calculated using the correct genetic parameter value. When the mode of genetic transmission is unknown, the maximum of the LOD scores obtained using several genetic parameter values is reported. This latter statistic requires higher critical value than the maximum LOD score statistic calculated from a single genetic parameter value. In this paper, we compare the power of maximum LOD scores based on three fixed sets of genetic parameter values with the power of the LOD score obtained after maximizing over the entire range of genetic parameter values. We simulate family data under nine generating models. For generating models with non-zero phenocopy rates, LOD scores maximized over the entire range of genetic parameters yielded greater power than maximum LOD scores for fixed sets of parameter values with zero phenocopy rates. No maximum LOD score was consistently more powerful than the others for generating models with a zero phenocopy rate. The power loss of the LOD score maximized over the entire range of genetic parameters, relative to the maximum LOD score calculated using the correct genetic parameter value, appeared to be robust to the generating models.

The solar energy is used as power source in photovoltaic power systems and the need for an intelligent power management system is important to obtain the maximumpower from the limited solar panels. With the changing of the sun illumination due to variation of angle of incidence of sun radiation and of the temperature of the panels, MaximumPower Point Tracker (MPPT) enables optimization of solar powergeneration. The MPPT is a sub-system designed to extract the maximumpower from a power source. In the case of solar panels power source. the maximumpower point varies as a result of changes in its electrical characteristics which in turn are functions of radiation dose, temperature, ageing and other effects. The MPPT maximum the power output from panels for a given set of conditions by detecting the best working point of the power characteristic and then controls the current through the panels or the voltage across them. Many MPPT methods have been reported in literature. These techniques of MPPT can be classified into three main categories that include: lookup table methods, hill climbing methods and computational methods. The techniques vary according to the degree of sophistication, processing time and memory requirements. The perturbation and observation algorithm (hill climbing technique) is commonly used due to its ease of implementation, and relative tracking efficiency. However, it has been shown that when the insolation changes rapidly, the perturbation and observation method is slow to track the maximumpower point. In recent years, the fuzzy controllers are used for maximumpower point tracking. This method only requires the linguistic control rules for maximumpower point, the mathematical model is not required and therefore the implementation of this control method is easy to real control system. In this paper, we we present a simple robust MPPT using fuzzy set theory where the hardware consists of the microchip's microcontroller unit control card and

An analysis of the thermal efficiency of a magnetohydrodynamic (MHD) power cycle at maximumpower density for a constant velocity type MHD generator has been carried out. The irreversibilities at the compressor and the MHD generator are taken into account. The results obtained from power density analysis were compared with those of maximumpower analysis. It is shown that by using the power density criteria the MHD cycle efficiency can be increased effectively. (author)

The frost in February increased the power demand in Finland significantly. The total power consumption in Finland during January-February 2001 was about 4% higher than a year before. In January 2001 the average temperature in Finland was only about - 4 deg C, which is nearly 2 degrees higher than in 2000 and about 6 degrees higher than long term average. Power demand in January was slightly less than 7.9 TWh, being about 0.5% less than in 2000. The power consumption in Finland during the past 12 months exceeded 79.3 TWh, which is less than 2% higher than during the previous 12 months. In February 2001 the average temperature was - 10 deg C, which was about 5 degrees lower than in February 2000. Because of this the power consumption in February 2001 increased by 5%. Power consumption in February was 7.5 TWh. The maximum hourly output of power plants in Finland was 13310 MW. Power consumption of Finnish households in February 2001 was about 10% higher than in February 2000, and in industry the increase was nearly zero. The utilization rate in forest industry in February 2001 decreased from the value of February 2000 by 5%, being only about 89%. The power consumption of the past 12 months (Feb. 2000 - Feb. 2001) was 79.6 TWh. Generation of hydroelectric power in Finland during January - February 2001 was 10% higher than a year before. The generation of hydroelectric power in Jan. - Feb. 2001 was nearly 2.7 TWh, corresponding to 17% of the power demand in Finland. The output of hydroelectric power in Finland during the past 12 months was 14.7 TWh. The increase from the previous 12 months was 17% corresponding to over 18% of the power demand in Finland. Wind powergeneration in Jan. - Feb. 2001 was exceeded slightly 10 GWh, while in 2000 the corresponding output was 20 GWh. The degree of utilization of Finnish nuclear power plants in Jan. - Feb. 2001 was high. The output of these plants was 3.8 TWh, being about 1% less than in Jan. - Feb. 2000. The main cause for the

Zipf's law, and power laws in general, have attracted and continue to attract considerable attention in a wide variety of disciplines—from astronomy to demographics to software structure to economics to linguistics to zoology, and even warfare. A recent model of random group formation (RGF) attempts a general explanation of such phenomena based on Jaynes' notion of maximum entropy applied to a particular choice of cost function. In the present paper I argue that the specific cost function used in the RGF model is in fact unnecessarily complicated, and that power laws can be obtained in a much simpler way by applying maximum entropy ideas directly to the Shannon entropy subject only to a single constraint: that the average of the logarithm of the observable quantity is specified. (paper)

In this paper, we consider the Wind Farm layout optimization problem using a genetic algorithm. Both the Horizontal –Axis Wind Turbines (HAWT) and Vertical-Axis Wind Turbines (VAWT) are considered. The goal of the optimization problem is to optimally position the turbines within the wind farm such that the wake effects are minimized and the power production is maximized. The reasonably accurate modeling of the turbine wake is critical in determination of the optimal layout of the turbines and the powergenerated. For HAWT, two wake models are considered; both are found to give similar answers. For VAWT, a very simple wake model is employed.

, as compared to the non-interacting system, in a wide range of biologically compatible scenarios. We furthermore consider the case where the motor-motor interaction directly affects the internal chemical cycle and investigate the effect on the system dynamics and thermodynamics.......We study the mechanical and thermodynamic properties of different traffic models for kinesin which are relevant in biological and experimental contexts. We find that motor-motor interactions play a fundamental role by enhancing the thermodynamic efficiency at maximumpower of the motors...

Full Text Available With the aim of reducing the hardware requirements in micro-grids based on wind generators, a distributed maximumpower point tracking algorithm is proposed. Such a solution reduces the amount of current sensors and processing devices to maximize the power extracted from the micro-grid, reducing the application cost. The analysis of the optimal operating points of the wind generator was performed experimentally, which in addition provides realistic model parameters. Finally, the proposed solution was validated by means of detailed simulations performed in the power electronics software PSIM, contrasting the achieved performance with traditional solutions.

Jun 30, 2010 ... Basic structure photovoltaic system Solar array mathematic ... The equivalent circuit model of a solar cell consists of a current generator and a diode .... control of boost converter (tracker) such that maximumpower is achieved at the output of the solar panel. Fig.11. The membership function of input. Fig.12.

Full Text Available Solar panels, which have become a good choice, are used to generate and supply electricity in commercial and residential applications. This generatedpower starts with the solar cells, which have a complex relationship between solar irradiation, temperature, and output power. For this reason a tracking of the maximumpower point is required. Traditionally, this has been made by considering just current and voltage conditions at the photovoltaic panel; however, temperature also influences the process. In this paper the voltage, current, and temperature in the PV system are considered to be a part of a sliding surface for the proposed maximumpower point tracking; this means a sliding mode controller is applied. Obtained results gave a good dynamic response, as a difference from traditional schemes, which are only based on computational algorithms. A traditional algorithm based on MPPT was added in order to assure a low steady state error.

This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine powergeneration systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine requires a power electronic converter to convert a variable voltage variable frequency source into a fixed voltage fixed frequency supply. Generic single-phase and three-phase converter topologies, converter control methods for wind powergeneration, as well as the developed direct drive generator, are introduced in the thesis for establishing variable-speed wind energy conversion systems. Variable speed wind powergeneration system modeling and simulation are essential methods both for understanding the system behavior and for developing advanced system control strategies. Wind generation system components, including wind turbine, 1-phase IGBT inverter, 3-phase IGBT inverter, synchronous generator, and rectifier, are modeled in this thesis using MATLAB/SIMULINK. The simulation results have been verified by a commercial simulation software package, PSIM, and confirmed by field test results. Since the dynamic time constants for these individual models are much different, a creative approach has also been developed in this thesis to combine these models for entire wind powergeneration system simulation. An advanced maximum wind energy extraction strategy relies not only on proper system hardware design, but also on sophisticated software control algorithms. Based on literature review and computer simulation on wind turbine control algorithms, an intelligent maximum wind energy extraction control algorithm is proposed in this thesis. This algorithm has a unique on-line adaptation and optimization capability, which is able to achieve maximum wind energy conversion efficiency through

The maximum auroral kilometric radiation (AKR) power flux observed by distant satellites has been increased by more than a factor of 10 from previously reported values. This increase has been achieved by a new data selection criterion and a new analysis of antenna spin modulated signals received by the radio astronomy instrument on ISEE 3. The method relies on selecting AKR events containing signals in the highest-frequency channel (1980, kHz), followed by a careful analysis that effectively increased the instrumental dynamic range by more than 20 dB by making use of the spacecraft antenna gain diagram during a spacecraft rotation. This analysis has allowed the separation of real signals from those created in the receiver by overloading. Many signals having the appearance of AKR harmonic signals were shown to be of spurious origin. During one event, however, real second harmonic AKR signals were detected even though the spacecraft was at a great distance (17 R E ) from Earth. During another event, when the spacecraft was at the orbital distance of the Moon and on the morning side of Earth, the power flux of fundamental AKR was greater than 3 x 10 -13 W m -2 Hz -1 at 360 kHz normalized to a radial distance r of 25 R E assuming the power falls off as r -2 . A comparison of these intense signal levels with the most intense source region values (obtained by ISIS 1 and Viking) suggests that multiple sources were observed by ISEE 3

As far as the past performances of power supply and demand in Korea is concerned, one of the striking phenomena is that there have been repeated periodic surpluses and shortages of powergeneration facilities. Precise assumption and prediction of power demands is the basic work in establishing a supply plan and carrying out the right policy since facilities investment of the powergeneration industry requires a tremendous amount of capital and a long construction period. The purpose of this study is to study a model for the inference and prediction of a more precise maximum demand under these backgrounds. The non-parametric model considered in this study, paying attention to meteorological factors such as temperature and humidity, does not have a simple proportionate relationship with the maximumpower demand, but affects it through mutual complicated nonlinear interaction. I used the non-parametric inference technique by introducing meteorological effects without importing any literal assumption on the interaction of temperature and humidity preliminarily. According to the analysis result, it is found that the non-parametric model that introduces the number of tropical nights which shows the continuity of the meteorological effect has better prediction power than the linear model. The non- parametric model that considers both the number of tropical nights and the number of cooling days at the same time is a model for predicting maximum demand. 7 refs., 6 figs., 9 tabs.

The concept of MHD powergeneration, principles of operation of the MHD generator, its design, types, MHD generator cycles, technological problems to be overcome, the current state of the art in USA and USSR are described. Progress of India's experimental 5 Mw water-gas fired open cycle MHD powergenerator project is reported in brief. (M.G.B.)

Accurate modeling and maximumpower point detection of photovoltaic ... Determination of MPP enables the PV system to deliver maximum available power. ..... adaptive artificial neural network: Proposition for a new sizing procedure.

Full Text Available It is well-known that energy harvesting from wind can be used to power remote monitoring systems. There are several studies that use wind energy in small-scale systems, mainly with wind turbine vertical axis. However, there are very few studies with actual implementations of small wind turbines. This paper compares the performance of horizontal and vertical axis wind turbines for energy harvesting on wireless sensor network applications. The problem with the use of wind energy is that most of the time the wind speed is very low, especially at urban areas. Therefore, this work includes a study on the wind speed distribution in an urban environment and proposes a controller to maximize the energy transfer to the storage systems. The generatedpower is evaluated by simulation and experimentally for different load and wind conditions. The results demonstrate the increase in efficiency of wind generators that use maximumpower transfer tracking, even at low wind speeds.

In view of the huge power demand in future, the capital investment requirements for the development of power projects to meet the future energy requirements are so alarming that public sector alone cannot manage to raise funds and participation of the private sector in powergeneration development has become imperative. This paper discusses a powergeneration philosophy based on preference to the exploitation of indigenous resources and participation of private sector. In order to have diversification in generation resources, due consideration has been given to the development of nuclear power and even non-conventional but promising technologies of solar, wind, biomass and geothermal etc. (author)

Highlights: • We implement a wind electric pumping system of small power. • The power converter allowed to change the operating point of the electro pump. • Two control techniques were implemented in the power converter. • The control V/f variable allowed to increase the powergenerated by the permanent magnet generator. - Abstract: In this work, an AC–DC–AC direct-drive power converter was implemented for a wind electric pumping system consisting of a permanent magnet generator (PMG) of 1.3 kW and a peripheral single phase pump of 0.74 kW. In addition, the inverter linear V/f control scheme and the maximumpower point tracking (MPPT) algorithm with variable V/f were developed. MPPT algorithm seeks to extract water in a wide range of power input using the maximum amount of wind power available. Experimental trials at different pump pressures were conducted. With a MPPT tracking system with variable V/f, a power value of 1.3 kW was obtained at a speed of 350 rpm and a maximum operating hydraulic head of 50 m. At lower operating heads pressures (between 10 and 40 m), variable V/f control increases the powergenerated by the PMG compared to the linear V/f control. This increase ranged between 4% and 23% depending on the operating pressure, with an average of 13%, getting close to the maximum electrical power curve of the PMG. The pump was driven at variable frequency reaching a minimum speed of 0.5 times the rated speed. Efficiency of the power converter ranges between 70% and 95% with a power factor between 0.4 and 0.85, depending on the operating pressure

The new edition of PowerGeneration Technologies is a concise and readable guide that provides an introduction to the full spectrum of currently available powergeneration options, from traditional fossil fuels and the better established alternatives such as wind and solar power, to emerging renewables such as biomass and geothermal energy. Technology solutions such as combined heat and power and distributed generation are also explored. However, this book is more than just an account of the technologies - for each method the author explores the economic and environmental costs and risk factor

This paper presents a microprocessor controlled maximumpower point tracker for photovoltaic module. Input current and voltage are measured and multiplied within the microprocessor, which contains an algorithm to seek the maximumpower point. The duly cycle of the DC-DC converter, at which the maximumpower occurs is obtained, noted and adjusted. The microprocessor constantly seeks for improvement of obtained power by varying the duty cycle

Microbial fuel cell (MFC) that can directly generate electricity from organic waste or biomass is a promising renewable and clean technology. However, low power and low voltage output of MFCs typically do not allow directly operating most electrical applications, whether it is supplementing electricity to wastewater treatment plants or for powering autonomous wireless sensor networks. Power management systems (PMSs) can overcome this limitation by boosting the MFC output voltage and managing the power for maximum efficiency. We present a monolithic low-power-consuming PMS integrated circuit (IC) chip capable of dynamic maximumpower point tracking (MPPT) to maximize the extracted power from MFCs, regardless of the power and voltage fluctuations from MFCs over time. The proposed PMS continuously detects the maximumpower point (MPP) of the MFC and matches the load impedance of the PMS for maximum efficiency. The system also operates autonomously by directly drawing power from the MFC itself without any external power. The overall system efficiency, defined as the ratio between input energy from the MFC and output energy stored into the supercapacitor of the PMS, was 30%. As a demonstration, the PMS connected to a 240 mL two-chamber MFC (generating 0.4 V and 512 μW at MPP) successfully powered a wireless temperature sensor that requires a voltage of 2.5 V and consumes power of 85 mW each time it transmit the sensor data, and successfully transmitted a sensor reading every 7.5 min. The PMS also efficiently managed the power output of a lower-power producing MFC, demonstrating that the PMS works efficiently at various MFC power output level.

The monthly statistics of wind electric powergeneration in Denmark are compiled from information given by the owners of the private wind turbines. For each wind turbine the name of the site and of the type of turbine is given, and the powergeneration data are given for the month in question together with the total production in 1999 and 2000. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. (CLS)

The monthly statistics of wind electric powergeneration in Denmark are compiled from information given by the owners of the private wind turbines. For each wind turbine the name of the site and of the type of turbine is given, and the powergeneration data are given for the month in question together with the total production in 2000 and 2001. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. (SM)

The future impact of the arrival of natural gas in the Maritime provinces on electricity generation in the region was discussed. Currently, electrical generation sources in Nova Scotia include hydro generation (9 per cent), coal generation (80 per cent), heavy fuel oil generation (8 per cent), and light oil, wood chips and purchased power (3 per cent). It is expected that with the introduction of natural gas electric utilities will take advantage of new gas combustion turbines which have high efficiency rates. An overview of Westcoast Power's operations across Canada was also presented. The Company has three projects in the Maritimes - the Courtney Bay project in New Brunswick, the Bayside Power project, the Irving Paper project - in addition to the McMahon cogeneration plant in Taylor, B.C. figs

The existing powergenerating device consisting of static components only lacks effective measures to utilize solar energy and maintain powergeneration, hence it is inevitable to make the device much larger and more complicated in order to utilize it as the primary power source for artificial satellites. In view of the above, in order to offer a powergenerating device useful for the primary power source for satellites which is simple and can keep powergeneration by solar energy, this invention proposes a powergenerating device composed of the following elements: (1) a rectangular parallelopiped No. II superconductor plate; (2) a measure to apply a magnetic field to one face of the above superconductor plate; (3) a measure to provide a temperature difference within the range between the starting temperature and the critical temperature of superconductivity to a pair of faces meeting at right angles with the face to which the magnetic field was applied by the above measure; (4) a measure to provide an electrode on each of the other pair of faces meeting at right angles with the face to which the magnetic field was applied by the above measure and form a closed circuit by connecting the each electrode above to each of a pair of electrodes of the load respectively; and (5) a switching measure which is installed in the closed circuit prepared by the above measure and shuts off the closed circuit when the direction of the electric current running the above closed circuit is reversed. 6 figs.

Apart from discussing some principles of power industry the present text deals with the different ways of electric powergeneration. Both the conventional methods of energy conversion in heating and water power stations and the facilities for utilizing regenerative energy sources (sun, wind, ground heat, tidal power) are considered. The script represents the essentials of the lecture of the same name which is offered to the students of the special subject 'electric power engineering' at the Fachhochschule Hamburg. It does not require any special preliminary knowledge except for the general principles of electrical engineering. It is addressing students of electrical engineering who have passed their preliminary examination at technical colleges and universities. Moreover, it shall also be of use for engineers who want to obtain a quick survey of the structure and the operating characteristics of the extremely different technical methods of powergeneration. (orig.) [de

This comprehensive report for the Swiss Federal Office of Energy (SFOE) takes a look at how the efficiency potential of heat pumps together with combined heat and power systems can help provide a maximum reduction of CO 2 emissions and provide electricity generation from fossil fuel in Switzerland together with reductions in CO 2 emissions. In Switzerland, approximately 80% of the low-temperature heat required for space-heating and for the heating-up of hot water is produced by burning combustibles. Around a million gas and oil boilers were in use in Switzerland in 2000, and these accounted for approximately half the country's 41.1 million tonnes of CO 2 emissions. The authors state that there is a more efficient solution with lower CO 2 emissions: the heat pump. With the enormous potential of our environment it would be possible to replace half the total number of boilers in use today with heat pumps. This would be equivalent to 90 PJ p.a. of useful heat, or 500,000 systems. The power source for heat pumps should come from the substitution of electric heating systems (electric resistor-based systems) and from the replacement of boilers. This should be done by using combined heat and power systems with full heat utilisation. This means, according to the authors, that the entire required power source can be provided without the need to construct new electricity production plants. The paper examines and discusses the theoretical, technical, market and realisable potentials

Nuclear powergeneration for commercial use in Japan has passed 35 years since beginning of operation in the Tokai Nuclear Power Station in 1966, and has 51 machines of reactor and about 44.92 MW of total output of equipment scale in the 21st century. However, an environment around nuclear energy becomes severer at present, and then so many subjects to be overcome are remained such as increased unreliability of the public on nuclear energy at a chance of critical accident of the JCO uranium processing facility, delay of pull-thermal plan, requirement for powergeneration cost down against liberalization of electric power, highly aging countermeasure of power plant begun its operation as its Genesis, and so on. Under such conditions, in order that nuclear powergeneration in Japan survives as one of basic electric source in future, it is necessary not only to pursue safety and reliability of the plant reliable to the public, but also to intend to upgrade its operation and maintenance by positively adopting good examples on operational management method on abroad and to endeavor further upgrading of application ratio of equipments and reduction of generation cost. Here were outlined on operation conditions of nuclear power stations in Japan, and introduced on upgrading of their operational management and maintenance management. (G.K.)

The French nuclear generating industry is highly competitive. The installations have an average age of fifteen years and are half way through their expected life. Nuclear power accounts for 70% of the profits of the French generating company, EDF. Nuclear generation has a minimal effect on the atmosphere and France has a level of CO 2 emissions, thought to be the main cause of the greenhouse effect, half that of Europe as a whole. The air in France is purer than in neighbouring countries, mainly because 75% of all electrical power is generated in nuclear plants and 15% in hydroelectric stations. The operations and maintenance of French nuclear power plants in the service and distribution companies out of a total of 100 000 employees in all, 90 % of whom are based in mainland France. (authors)

During the wind powergenerator project a design algorithm for a gearless permanent magnet generator with an axially orientated magnetic flux was developed and a 10 kW model machine was constructed. Utilising the test results a variable wind speed system of 100 kW was designed that incorporates a permanent magnet generator, a frequency converter and a fuzzy controller. This system produces about 5-15% more energy than existing types and stresses to the blades are minimised. The type of generator designed in the project represents in general a gearless solution for slow-speed electrical drives. (orig.)

A peak power ratio generator is described for measuring, in combination with a conventional power meter, the peak power level of extremely narrow pulses in the gigahertz radio frequency bands. The present invention in a preferred embodiment utilizes a tunnel diode and a back diode combination in a detector circuit as the only high speed elements. The high speed tunnel diode provides a bistable signal and serves as a memory device of the input pulses for the remaining, slower components. A hybrid digital and analog loop maintains the peak power level of a reference channel at a known amount. Thus, by measuring the average power levels of the reference signal and the source signal, the peak power level of the source signal can be determined.

Tethering cable was investigated as a part of a research of jet stream powergeneration using balloon and kite. Recently, there appeared new materials with light and high strength properties, such as carbon and polyamide resin. When these are used as tethering cables, flying ability of tethered bodies is remarkably improved. Tethered balloon at the altitude of 6500 feet and large-scale kite at the altitude of 5000 m are proposed for the idea of jet stream powergeneration. A computer program was developed for determining the flying ability of a kite, to calculate it. Similarity rule was also determined by the dimensional analysis. For a kite with a tethering cable having uniform diameter and specific gravity, the similarity can be obtained when two kinds of similarity rules are satisfied. One is (length of tethering cable/width of kite wing)times(dynamic pressure of air/tensile strength of cable){sup 1/2}=(constant). Another is (length of tethering cable)times(density of cable/tensile strength of cable)=(constant). Since the maximum height is in proportion to (strength/specific gravity) of the cable, it increases drastically using high performance materials. It is affected by the aerodynamic performance of the kite and the safety factor of strength of the cable. 4 refs., 45 figs., 2 tabs.

The monthly statistics of wind electric powergeneration in Denmark are compiled from information given by the owners of private wind turbines. For each wind turbine the name of the site and of the type of turbine is given, and the powergeneration data are given for the month in question together with the total production in 1988 and 1989. Also the data of operation start are given. On the map of Denmark the sites of the wind turbines are marked. The statistics for December 1994 comprise 2328 wind turbines

The paper describes research and development in the field of magnetohydrodynamic powergeneration technology, based on discussions held in the Joint IAEA/UNESCO International Liaison Group on MHD electrical powergeneration. Research and development programmes on open cycle, closed cycle plasma and liquid-metal MHD are described. Open cycle MHD has now entered the engineering development stage. The paper reviews the results of cycle analyses and economic and environmental evaluations: substantial agreement has been reached on the expected overall performance and necessary component specifications. The achievement in the Soviet Union on the U-25 MHD pilot plant in obtaining full rated electrical power of 20.4 MW is described, as well as long duration testing of the integrated operation of MHD components. Work in the United States on coal-fired MHD generators has shown that, with slagging of the walls, a run time of about one hundred hours at the current density and electric field of a commercial MHD generator has been achieved. Progress obtained in closed cycle plasma and liquid metal MHD is reviewed. Electrical power densities of up to 140 MWe/m 3 and an enthalpy extraction as high as 24 per cent have been achieved in noble gas MHD generator experiments. (Auth.)

Indian experience pertaining to investment and generation costs of nuclear power stations is reviewed. The causes of investment cost increases are analysed and the increases are apportioned to escalation, design improvements and safety related adders. The paper brings out the fact that PHWR investment costs in India compare favourably with those experienced in developed countries in spite of the fact that the programme and the unit size are relatively much smaller in India. It brings out that in India at current prices a nuclear power station located over 800 km from coal reserves and operating at 75% capacity factor is competitive with thermal power at 60% capacity factor. (author)

A comparison is made between the various ways of powergeneration in the Netherlands and the hazards attached to them. Tables are presented of fuels used, the quantities used per annum and in the course of the last 20 years, accidents and pollution types and percentages, as well as the toxicity and waste disposal risks. (Auth.)

knee point of PV system under variable atmospheric conditions have been ..... of the PV generator module increases, and the maximumpower output increases as well. ..... Water Pumping System” A Thesis resented to the. Faculty of California ...

The book includes an introduction then it speaks about the options to secure sources of energy, nuclear power option, nuclear plants to generate energy including light-water reactors (LWR), heavy-water reactors (HWR), advanced gas-cooled reactors (AGR), fast breeder reactors (FBR), development in the manufacture of reactors, fuel, uranium in the world, current status of nuclear powergeneration, economics of nuclear power, nuclear power and the environment and nuclear power in the Arab world. A conclusion at the end of the book suggests the increasing demand for energy in the industrialized countries and in a number of countries that enjoy special and economic growth such as China and India pushes the world to search for different energy sources to insure the urgent need for current and anticipated demand in the near and long-term future in light of pessimistic and optimistic outlook for energy in the future. This means that states do a scientific and objective analysis of the currently available data for the springboard to future plans to secure the energy required to support economy and welfare insurance.

An electric powergenerator of the type employing a nuclear heat source and a thermoelectric converter is described wherein a transparent thermal insulating medium is provided inside an encapsulating enclosure to thermally insulate the heat source and thermoelectric generator. The heat source, the thermoelectric converter, and the enclosure are provided with facing surfaces which are heat-reflective to a substantial degree to inhibit radiation of heat through the medium of the encapsulating enclosure. Multiple reflective foils may be spaced within the medium as necessary to inhibit natural convection of heat and/or further inhibit radiation

The monthly statistics of wind electric powergeneration in Denmark are compiled from information given by the owners of private wind turbines. The data are arranged according to the size of the turbines. For each wind turbine the name of the site and type of turbine is given as well as the production during the last 3 months in 1998, and the total production in 1997 and 1998. Data on the operation is given

A historical background on windmill use, the nature of wind, wind conversion system technology and requirements, the economics of wind power and comparisons with alternative systems, data needs, technology development needs, and an implementation plan for wind energy are presented. Considerable progress took place during the 1950's. Most of the modern windmills feature a wind turbine electricity generator located directly at the top of their rotor towers.

Processes to produce hydrogen from solar photovoltaic (PV)-powered water electrolysis using solid polymer electrolysis (SPE) are reported. An alternative control of maximumpower point tracking (MPPT) in the PV-SPE system based on the maximum current searching methods has been designed and implemented. Based on the characteristics of voltage-current and theoretical analysis of SPE, it can be shown that the tracking of the maximum current output of DC-DC converter in SPE side will track the MPPT of photovoltaic panel simultaneously. This method uses a proportional integrator controller to control the duty factor of DC-DC converter with pulse-width modulator (PWM). The MPPT performance and hydrogen production performance of this method have been evaluated and discussed based on the results of the experiment. (Author)

Full Text Available Photovoltaic electricity is seen as an important source of renewable energy. The photovoltaic array is an unstable source of power since the peak power point depends on the temperature and the irradiation level. A maximum peak power point tracking is then necessary for maximum efficiency.In this work, a Particle Swarm Optimization (PSO is proposed for maximumpower point tracker for photovoltaic panel, are used to generate the optimal MPP, such that solar panel maximumpower is generated under different operating conditions. A photovoltaic system including a solar panel and PSO MPP tracker is modelled and simulated, it has been has been carried out which has shown the effectiveness of PSO to draw much energy and fast response against change in working conditions.

This job is developed as part of “Health aware enhanced range wireless power transfer systems", known as ETHER. It is a cooperation project where Universidad Politécnica de Madrid (UPM) and Universidad Politécnica de Cataluña (UPC) research groups are mainly involved. ETHER objective is to develop a wireless power transfer system for medical applications, specifically a pacemaker charger to improve patient’s lifestyle decreasing the number of required operations to replace pacemaker batter...

Under a certain temperature difference, the maximumpower of a thermoelectric module can be estimated by the open-circuit voltage and the short-circuit current. In practical measurement, there exist two switch modes, either from open to short or from short to open, but the two modes can give...... different estimations on the maximumpower. Using TEG-127-2.8-3.5-250 and TEG-127-1.4-1.6-250 as two examples, the difference is about 10%, leading to some deviations with the temperature change. This paper analyzes such differences by means of a nonlinear numerical model of thermoelectricity, and finds out...... that the main cause is the influence of various currents on the produced electromotive potential. A simple and effective calibration method is proposed to minimize the deviations in specifying the maximumpower. Experimental results validate the method with improved estimation accuracy....

PROTO II, a super powergenerator, is presently undergoing testing at Sandia Laboratories. It has operated with an 80 ns, 50 ns, 35 ns, and 20 ns positive output pulse high voltage mode and achieved total current rates of rise of 4 x 10 14 A/s. The two sided disk accelerator concept using two diodes has achieved voltages of 1.5 MV and currents of 4.5 MA providing a power exceeding 6 TW in the electron beam and 8 TW in the transmission lines. A new test bed named MITE (Magnetically Insulated Transmission Experiment) was designed and is now being tested. The pulse forming lines are back to back short pulse Blumleins which use untriggered water switching. Output data showing a ten ns half width power pulse peaking above one terrawatt were obtained. MITE is a module being investigated for use in the Electron Beam Fusion Accelerator and will be used to test the effects of short pulses propagating down vacuum transmission lines

Oregon Institute of Technology (OIT) drilled a deep geothermal well on campus (to 5,300 feet deep) which produced 196°F resource as part of the 2008 OIT Congressionally Directed Project. OIT will construct a geothermal power plant (estimated at 1.75 MWe gross output). The plant would provide 50 to 75 percent of the electricity demand on campus. Technical support for construction and operations will be provided by OIT’s Geo-Heat Center. The power plant will be housed adjacent to the existing heat exchange building on the south east corner of campus near the existing geothermal production wells used for heating campus. Cooling water will be supplied from the nearby cold water wells to a cooling tower or air cooling may be used, depending upon the type of plant selected. Using the flow obtained from the deep well, not only can energy be generated from the power plant, but the “waste” water will also be used to supplement space heating on campus. A pipeline will be construction from the well to the heat exchanger building, and then a discharge line will be construction around the east and north side of campus for anticipated use of the “waste” water by facilities in an adjacent sustainable energy park. An injection well will need to be drilled to handle the flow, as the campus existing injection wells are limited in capacity.

We consider nanosized artificial or biological machines working in steady state enforced by imposing nonequilibrium concentrations of solutes or by applying external forces, torques, or electric fields. For unicyclic and strongly coupled multicyclic machines, efficiency at maximumpower is not bounded by the linear response value 1/2. For strong driving, it can even approach the thermodynamic limit 1. Quite generally, such machines fall into three different classes characterized, respectively, as "strong and efficient," "strong and inefficient," and "balanced." For weakly coupled multicyclic machines, efficiency at maximumpower has lost any universality even in the linear response regime.

This paper introduces a polynomial fuzzy model (PFM)-based maximumpower point tracking (MPPT) control approach to increase the performance and efficiency of the solar photovoltaic (PV) electricity generation. The proposed method relies on a polynomial fuzzy modeling, a polynomial parallel......, a direct maximumpower (DMP)-based control structure is considered for MPPT. Using the PFM representation, the DMP-based control structure is formulated in terms of SOS conditions. Unlike the conventional approaches, the proposed approach does not require exploring the maximumpower operational point...

We propose a simple model for a motor that generates mechanical motion by exploiting an entropic force arising from the topology of the underlying phase space. We show that the generation of mechanical forces in our system is surprisingly robust to local changes in kinetic and topological paramet...... parameters. Furthermore, we find that the efficiency at maximumpower may show discontinuities....

Full Text Available The power supplied by any solar array depends upon the environmental conditions as weather conditions (temperature and radiation intensity and the incident angle of the radiant source. The work aims to study the maximumpower tracking schemes that used to compare the system performance without and with different types of controllers. The maximumpower points of the solar panel under test studied and compared with two controller's types. The first controller is the proportional- integral - derivative controller type and the second is the perturbation and observation algorithm controller. The associated converter system is a microcontroller based type, whereas the results studied and compared of greatest power point of the Photovoltaic panels under the different two controllers. The experimental tests results compared with simulation results to verify accurate performance.

The operating power of a reactor is an important parameter to be monitored. This report briefly describes the determining and monitoring of maximum permissiable power for HWRR-3. The calculating method is described, and the result of calculation and analysis of error are also given. On-line calculation and real time monitoring have been realized at the heavy water reactor. It provides the reactor with a real time and reliable supervision. This makes operation convenient and increases reliability

A heat-to-electricity converter is disclosed which includes a radioactive heat source and a thermoelectric element of relatively short overall length capable of delivering a low voltage of the order of a few tenths of a volt. Such a thermoelectric element operates at a higher efficiency than longer higher-voltage elements; for example, elements producing 6 volts. In the generation of required power, the thermoelectric element drives a solid-state converter which is controlled by input current rather than input voltage and operates efficiently for a high signal-plus-noise to signal ratio of current. The solid-state converter has the voltage gain necessary to deliver the required voltage at the low input of the thermoelectric element

Full Text Available The control strategies of the small power wind generator are usually divided into the maximumpower point tracking (MPPT case, which requires the wind generator produce power as much as possible, and the power limited control (PLC case that demands the wind generator produce a power level following the load requirement. Integration of these two operating cases responding to flexible and sophisticated power demands is the main topic of this article. A small power wind generator including the sluggish mechanical dynamic phenomenon, which uses the permanent magnet synchronous generator, is introduced to validate different control methods integrating MPPT and PLC cases and based on hysteresis control. It is a matter of an indirect power control method derived from three direct methods following perturb and observe principle as well as from a look-up table. To analyze and compare the proposed power control methods, which are implemented into an emulator of a small power wind generator, a power demand profile is used. This profile is randomly generated based on measured rapid wind velocity data. Analyzing experimental results, from the power viewpoint, all proposed methods reveal steady-state error with big amount of peak resulting from the nature of perturb and observe.

Nuclear power plays an important role in the world, European (33%) and French (75%) powergeneration. This article aims at presenting in a synthetic way the main reactor types with their respective advantages with respect to the objectives foreseen (powergeneration, resources valorization, waste management). It makes a fast review of 50 years of nuclear development, thanks to which the nuclear industry has become one of the safest and less environmentally harmful industry which allows to produce low cost electricity: 1 - simplified description of a nuclear powergeneration plant: nuclear reactor, heat transfer system, powergeneration system, interface with the power distribution grid; 2 - first historical developments of nuclear power; 3 - industrial development and experience feedback (1965-1995): water reactors (PWR, BWR, Candu), RBMK, fast neutron reactors, high temperature demonstration reactors, costs of industrial reactors; 4 - service life of nuclear power plants and replacement: technical, regulatory and economical lifetime, problems linked with the replacement; 5 - conclusion. (J.S.)

A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

Using the method of adjoint equations described in Ref. [1], we have calculated the maximum thermal efficiencies that are theoretically attainable by free-piston Stirling and Carnot engine generators by considering the work loss due to friction and Joule heat. The net work done by the Carnot cycle is negative even when the duration of heat addition is optimized to give the maximum amount of heat addition, which is the same situation for the Brayton cycle described in our previous paper. For the Stirling cycle, the net work done is positive, and the thermal efficiency is greater than that of the Otto cycle described in our previous paper by a factor of about 2.7-1.4 for compression ratios of 5-30. The Stirling cycle is much better than the Otto, Brayton, and Carnot cycles. We have found that the optimized piston trajectories of the isothermal, isobaric, and adiabatic processes are the same when the compression ratio and the maximum volume of the same working fluid of the three processes are the same, which has facilitated the present analysis because the optimized piston trajectories of the Carnot and Stirling cycles are the same as those of the Brayton and Otto cycles, respectively.

In the project a 100 kW axial flux permanent magnet wind powergenerator has been designed. The toroidal stator with air gap winding is placed between two rotating discs with permanent magnets. The magnet material is NdBFe due to its excellent magnetic properties compared to other materials. This type of topology enables a very large number of poles compared to conventional machine of the same size. A large number of poles is required to achieve a low rotational speed and consequently a direct driven system. The stator winding is formed by rectangular coils. The end winding is very short leading to small resistive losses. On the other hand, the absence of iron teeth causes eddy current losses in the conductors. These can be restricted to an acceptable level by keeping the wire diameter and flux density small. This means that the number of phases should be large. Several independent three phase systems may be used. The toothless stator also means that the iron losses are small and there exists no cogging torque

Fossil fuel based powergeneration is and will still be the back bone of our world economy, albeit such form of powergeneration significantly contributes to global CO 2 emissions. Solar energy is a clean, environmental friendly energy source for powergeneration, however solar photovoltaic electricity generation is not practical for large commercial scales due to its cost and high-tech nature. Solar thermal is another way to use solar energy to generatepower. Many attempts to establish solar (solo) thermal power stations have been practiced all over the world. Although there are some advantages in solo solar thermal power systems, the efficiencies and costs of these systems are not so attractive. Alternately by modifying, if possible, the existing coal-fired power stations to generate green sustainable power, a much more efficient means of powergeneration can be reached. This paper presents the concept of solar aided powergeneration in conventional coal-fired power stations, i.e., integrating solar (thermal) energy into conventional fossil fuelled powergeneration cycles (termed as solar aided thermal power). The solar aided powergeneration (SAPG) concept has technically been derived to use the strong points of the two technologies (traditional regenerative Rankine cycle with relatively higher efficiency and solar heating at relatively low temperature range). The SAPG does not only contribute to increase the efficiencies of the conventional power station and reduce its emission of the greenhouse gases, but also provides a better way to use solar heat to generate the power. This paper presents the advantages of the SAPG at conceptual level.

Full Text Available In applications with low-energy conversion efficiency, maximizing the output power improves the efficiency. The maximum output power of a solar panel depends on the environmental conditions and load profile. In this paper, a method based on simultaneous use of two fuzzy controllers is developed in order to maximize the generated output power of a solar panel in a photovoltaic system: fuzzy-based sun tracking and maximumpower point tracking. The sun tracking is performed by changing the solar panel orientation in horizontal and vertical directions by two DC motors properly designed. A DC-DC converter is employed to track the solar panel maximumpower point. In addition, the proposed system has the capability of the extraction of solar panel I-V curves. Experimental results present that the proposed fuzzy techniques result in increasing of power delivery from the solar panel, causing a reduction in size, weight, and cost of solar panels in photovoltaic systems.

Full Text Available Photovoltaic (PV system has a great potential and it is installed more when compared with other renewable energy sources nowadays. However, the PV system cannot perform optimally due to its solid reliance on climate conditions. Due to this dependency, PV system does not operate at its maximumpower point (MPP. Many MPP tracking methods have been proposed for this purpose. One of these is the Perturb and Observe Method (P&O which is the most famous due to its simplicity, less cost and fast track. But it deviates from MPP in continuously changing weather conditions, especially in rapidly changing irradiance conditions. A new MaximumPower Point Tracking (MPPT method, Tetra Point Perturb and Observe (TPPO, has been proposed to improve PV system performance in changing irradiance conditions and the effects on characteristic curves of PV array module due to varying irradiance are delineated. The Proposed MPPT method has shown better results in increasing the efficiency of a PV system.

Full Text Available In this paper, the implementation of the MaximumPower Point Tracking (MPPT technique is developed using buck-boost converter. Perturb and observe (P&O MPPT algorithm is used to searching maximumpower from the wind power plant for charging of the battery. The model used in this study is the Variable Speed Wind Turbine (VSWT with a Permanent Magnet Synchronous Generator (PMSG. Analysis, design, and modeling of wind energy conversion system has done using MATLAB/simulink. The simulation results show that the proposed MPPT produce a higher output power than the system without MPPT. The average efficiency that can be achieved by the proposed system to transfer the maximumpower into battery is 90.56%.

Highlights: • Feedforward MPPT scheme for uninterrupted TEG energy harvesting is suggested. • Temperature sensors are used to avoid current measurement or source disconnection. • MPP voltage reference is generated based on OCV vs. temperature differential model. • Optimal operating condition is maintained using hysteresis controller. • Any type of power converter can be used in the proposed scheme. - Abstract: In this paper, a thermoelectric generator (TEG) energy harvesting system with a temperature-sensor-based maximumpower point tracking (MPPT) method is presented. Conventional MPPT algorithms for photovoltaic cells may not be suitable for thermoelectric powergeneration because a significant amount of time is required for TEG systems to reach a steady state. Moreover, complexity and additional power consumption in conventional circuits and periodic disconnection of power source are not desirable for low-power energy harvesting applications. The proposed system can track the varying maximumpower point (MPP) with a simple and inexpensive temperature-sensor-based circuit without instantaneous power measurement or TEG disconnection. This system uses TEG’s open circuit voltage (OCV) characteristic with respect to temperature gradient to generate a proper reference voltage signal, i.e., half of the TEG’s OCV. The power converter controller maintains the TEG output voltage at the reference level so that the maximumpower can be extracted for the given temperature condition. This feedforward MPPT scheme is inherently stable and can be implemented without any complex microcontroller circuit. The proposed system has been validated analytically and experimentally, and shows a maximumpower tracking error of 1.15%

Powergeneration from renewable energy sources is different from powergeneration from classical energies (nuclear, thermal..). Therefore, the integration into the grid of the electricity supplied by renewable sources requires a deep thinking. The reason is that these power sources are controlled by variable elements, like wind, water and sun, which condition production. This book deals with the following aspects in detail: characteristics of classical and intermittent generators; grid balancing between supply and demand; conversion methods of renewable energies into electricity; power systems; privatizing of powergeneration and birth of new markets, in particular the 'green' power market; development of renewable energies thanks to technical advances. It gives a comprehensive overview of the present day available renewable energy sources for powergeneration. (J.S.)

Full Text Available The most primitive control method of wind turbines used to generate electric energy from wind is the fixed speed control method. With this method, it is not possible that turbine input power is transferred to grid at maximum rate. For this reason, MaximumPower Tracking (MPT schemes are proposed. In order to implement MPT, the propeller has to rotate at a different speed for every different wind speed. This situation has led MPT based systems to be called Variable Speed Wind Turbine (VSWT systems. In VSWT systems, turbine input power can be transferred to grid at rates close to maximumpower. When MPT based control of VSWT systems is the case, two important processes come into prominence. These are instantaneously determination and tracking of MPT point. In this study, using a MaximumPower Point Tracking (MPPT method based on tip speed ratio, power available in wind is transferred into grid over a back to back converter at maximum rate via a VSWT system with permanent magnet synchronous generator (PMSG. Besides a physical wind turbine simulator is modelled and simulated. Results show that a time varying MPPT point is tracked with a high performance.

The paper presents the simulation and hardware implementation of maximumpower point (MPP) tracking of a partially shaded solar photovoltaic (PV) array using a variant of Particle Swarm Optimization known as Adaptive Perceptive Particle Swarm Optimization (APPSO). Under partially shaded conditions, the photovoltaic (PV) array characteristics get more complex with multiple maxima in the power-voltage characteristic. The paper presents an algorithmic technique to accurately track the maximumpower point (MPP) of a PV array using an APPSO. The APPSO algorithm has also been validated in the current work. The proposed technique uses only one pair of sensors to control multiple PV arrays. This result in lower cost and higher accuracy of 97.7% compared to earlier obtained accuracy of 96.41% using Particle Swarm Optimization. The proposed tracking technique has been mapped onto a MSP430FG4618 microcontroller for tracking and control purposes. The whole system based on the proposed has been realized on a standard two stage power electronic system configuration. (author)

There are many applications where thermoelectric (TE) coolers can be used effectively as powergenerators. The literature available on this subject is scarce and very limited in scope. This paper describes the configuration, capability, limitations and performance of TE coolers to be used as powergenerators. Also presented are performance curves enabling the user to design the optimum TE module for any given powergeneration application

The technique for calculating maximum permissible power of a research reactor at which the probability of the thermal-process accident does not exceed the specified value, is presented. The statistical method is used for the calculations. It is regarded that the determining function related to the reactor safety is the known function of the reactor power and many statistically independent values which list includes the reactor process parameters, geometrical characteristics of the reactor core and fuel elements, as well as random factors connected with the reactor specific features. Heat flux density or temperature is taken as a limiting factor. The program realization of the method discussed is briefly described. The results of calculating the PIK reactor margin coefficients for different probabilities of the thermal-process accident are considered as an example. It is shown that the probability of an accident with fuel element melting in hot zone is lower than 10 -8 1 per year for the reactor rated power [ru

This supplement volume contains 17 separate chapters investigating the parameters which determine powergeneration costs on the basis of coal and nuclear power and a comparison of these. A detailed calculation model is given. The complex nature of this type of cost comparison is shown by a review of selected parameter constellation for coal-fired and nuclear power plants. The most favourable method of powergeneration can only be determined if all parameters are viewed together. One quite important parameter is the load factor, or rather the hours of operation. (UA) 891 UA/UA 892 AMO [de

This book reviews environmental aspects of large-scale powergeneration. It includes historic background of present-generation patterns and a discussion of fossil fuel, nuclear energy, and renewable technologies

The voltage and current characteristic of a photovoltaic (PV) cell is highly nonlinear and operating a PV cell for maximumpower transfer has been a challenge for a long time. Several techniques have been proposed to estimate and track the maximumpower point (MPP) in order to improve the overall efficiency of a PV panel. A strategic use of the mean value theorem permits obtaining an analytical expression for a point that lies in a close neighborhood of the true MPP. But hitherto, an exact solution in closed form for the MPP is not published. This problem can be formulated analytically as a constrained optimization, which can be solved using the Lagrange method. This method results in a system of simultaneous nonlinear equations. Solving them directly is quite difficult. However, we can employ a recursive algorithm to yield a reasonably good solution. In graphical terms, suppose the voltage current characteristic and the constant power contours are plotted on the same voltage current plane, the point of tangency between the device characteristic and the constant power contours is the sought for MPP. It is subject to change with the incident irradiation and temperature and hence the algorithm that attempts to maintain the MPP should be adaptive in nature and is supposed to have fast convergence and the least misadjustment. There are two parts in its implementation. First, one needs to estimate the MPP. The second task is to have a DC-DC converter to match the given load to the MPP thus obtained. Availability of power electronics circuits made it possible to design efficient converters. In this paper although we do not show the results from a real circuit, we use MATLAB to obtain the MPP and a buck-boost converter to match the load. Under varying conditions of load resistance and irradiance we demonstrate MPP tracking in case of a commercially available solar panel MSX-60. The power electronics circuit is simulated by PSIM software.

Full Text Available The purpose of this paper is to present an alternative maximumpower point tracking, MPPT, algorithm for a photovoltaic module, PVM, to produce the maximumpower, Pmax, using the optimal duty ratio, D, for different types of converters and load matching.We present a state-based approach to the design of the maximumpower point tracker for a stand-alone photovoltaic powergeneration system. The system under consideration consists of a solar array with nonlinear time-varying characteristics, a step-up converter with appropriate filter.The proposed algorithm has the advantages of maximizing the efficiency of the power utilization, can be integrated to other MPPT algorithms without affecting the PVM performance, is excellent for Real-Time applications and is a robust analytical method, different from the traditional MPPT algorithms which are more based on trial and error, or comparisons between present and past states. The procedure to calculate the optimal duty ratio for a buck, boost and buck-boost converters, to transfer the maximumpower from a PVM to a load, is presented in the paper. Additionally, the existence and uniqueness of optimal internal impedance, to transfer the maximumpower from a photovoltaic module using load matching, is proved.

Full Text Available In this paper, a MaximumPower Point Tracking (MPPT controller for solar power system is modeled using MATLAB Simulink. The model consists of PV module, buck converter, and MPPT controller. The contribution of the work is in the modeling of buck converter that allowing the input voltage of the converter, i.e. output voltage of PV is changed by varying the duty cycle, so that the maximumpower point could be tracked when the environmental changes. The simulation results show that the developed model performs well in tracking the maximumpower point (MPP of the PV module using Perturb and Observe (P&O Algorithm.

Full Text Available At present, the bulk of the world is electricity is generated in central power stations. This approach, one of `economy of size generates electricity in large power stations and delivers it to load centres via an extensive network of transmission...

The power consumption in the common Nordic power market continues to grow. All potential production technologies entail more or less reduction in quality of the environment. This gives each of the Nordic countries incentives to limit the development of capacity and base themselves increasingly on import, which means that other countries take the political burden with the environmental issues (''free rider problem''). The uncertainty about the climate problem may make it rational to postpone investments which are expensive to reverse, like gas power. If the decisions are delayed too long, however, considerable socio-economic costs may accumulate because the price of electricity becomes too high. The present regulations of the environmental concerns in connection with the granting of concession are expensive and unpredictable and put society unnecessarily to expense

Highlights: • A novel approach for tracking the maximumpower point of photovoltaic systems. • Able to handle both the uniform insolation and partial shading conditions. • Maximumpower point tracking based on current sweeping. - Abstract: Partial shading on photovoltaic (PV) arrays causes multiple peaks on the output power–voltage characteristic curve and local searching technique such as perturb and observe (P&O) method could easily fail in searching for the global maximum. Moreover, existing global searching techniques are still not very satisfactory in terms of speed and implementation complexity. In this paper, a fast global maximumpower point (MPPT) tracking method which is using current sweeping for photovoltaic arrays under partial shading conditions is proposed. Unlike conventional approach, the proposed method is current based rather than voltage based. The initial maximumpower point will be derived based on a current sweeping test and the maximumpower point can be enhanced by a finer local search. The speed of the global search is mainly governed by the apparent time constant of the PV array and the generation of a fast current sweeping test. The fast current sweeping test can easily be realized by a DC/DC boost converter with a very fast current control loop. Experimental results are included to demonstrate the effectiveness of the proposed global searching scheme

There have been extensive developments in the power supply industry in South Africa. The most evident of these has been the increase in the size of generating units. Escom has recently placed orders for 600 MW units. In South Africa, with its large indigenous reserves of cheap coal, there was no need to rush into a nuclear power programme before it would be economic and, accordingly the first serious study of nuclear powergeneration was not undertaken until 1966. A final aspect of powergeneration which is becoming very important is the control of pollution and protection of the environment

In view of the various merits of nuclear powergeneration, Japanese electric utilities will continue to promote nuclear powergeneration. At the same time, however, it is essential to further enhance cost performance. Japanese electric utilities plan to reduce the cost of nuclear powergeneration, such as increasing the capacity factor, reducing operation and maintenance costs, and reducing construction costs. In Asia, nuclear power will also play an important role as a stable source of energy in the future. For those countries planning to newly introduce nuclear power, safety is the highest priority, and cost competitiveness is important. Moreover, financing will be an essential issue to be resolved. Japan is willing to support the establishment of nuclear powergeneration in Asia, through its experience and achievements. In doing this, support should not only be bilateral, but should include all nuclear nations around the Pacific rim in a multilateral support network. (author)

Renewable energy sources are the second largest contributor to global electricity production, after fossil fuels. The integration of renewable energy continued to grow in 2014 against a backdrop of increasing global energy consumption and a dramatic decline in oil prices during the second half of the year. As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded from primarily wind and solar to include new types with promising future applications, such as hydropower generation, including river and tidal generation. Today, hydropower is considered one of the most important renewable energy sources. In river and tidal generation, the input resource flow is slower but also steadier than it is in wind or solar generation, yet the level of water turbulent flow may vary from one place to another. This report focuses on hydrokinetic power conversion.

In the current context to encourage sustainable development, wind energy plays an important role in the spread of renewable energy sources. In this paper, the possibilities and difficulties of wind power integration in large-scale are evaluated, specifically in the northeastern region of Brazil. From the seasonal complementarity with the water source, scenarios are set out where the maximum participation of only these two sources in the energy supply of the region is sought. Aiming to evaluate the possibilities of a completely sustainable regional energy supply, the northeast subsystem is isolated, excluding, in principle, imports and exports. Therefore, the energy storage capacity of reservoirs in the region is used as a key factor, combined with the seasonal availability of data sources and the annual energy consumption of the region. (author)

Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant PowerGeneration (CPG) control method has been proposed at the inverter level...... devices, allowing a quantitative prediction of the power device lifetime. A study case on a 3 kW single-phase PV inverter has demonstrated the advantages of the CPG control in terms of improved reliability.......Grid operation experiences have revealed the necessity to limit the maximum feed-in power from PV inverter systems under a high penetration scenario in order to avoid voltage and frequency instability issues. A Constant PowerGeneration (CPG) control method has been proposed at the inverter level....... The CPG control strategy is activated only when the DC input power from PV panels exceeds a specific power limit. It enables to limit the maximum feed-in power to the electric grids and also to improve the utilization of PV inverters. As a further study, this paper investigates the reliability performance...

A powergeneration system includes a plurality of submerged mechanical devices. Each device includes a pump that can be powered, in operation, by mechanical energy to output a pressurized output liquid flow in a conduit. Main output conduits are connected with the device conduits to combine pressurized output flows output from the submerged mechanical devices into a lower number of pressurized flows. These flows are delivered to a location remote of the submerged mechanical devices for powergeneration.

Since publication of the second edition, there have been extensive changes in the algorithms, methods, and assumptions in energy management systems that analyze and control powergeneration. This edition is updated to acquaint electrical engineering students and professionals with current powergeneration systems. Algorithms and methods for solving integrated economic, network, and generating system analysis are provided. Also included are the state-of-the-art topics undergoing evolutionary change, including market simulation, multiple market analysis, multiple interchange contract analysis, c

This paper discusses the ideal voltage of steady-flow fuel cells usually expressed by Emf = -ΔG/nF where ΔG is the Gibbs free energy of reaction for the oxidation of the fuel at the supposed temperature of operation of the cell. Furthermore, the ideal power of the cell is expressed as the product of the fuel flow rate with this emf, and the efficiency of a real fuel cell, sometimes called the Gibbs efficiency, is defined as the ratio of the actual power output to this ideal power. Such viewpoints are flawed in several respects. While it is true that if a cell operates isothermally the maximum conceivable work output is equal to the difference between the Gibbs free energy of the incoming reactants and that of the leaving products, nevertheless, even if the cell operates isothermally, the use of the conventional ΔG of reaction assumes that the products of reaction leave separately from one another (and from any unused fuel), and when ΔS of reaction is positive it assumes that a free heat source exists at the operating temperature, whereas if ΔS is negative it neglects the potential power which theoretically could be obtained form the heat released during oxidation. Moreover, the usual cell does not operate isothermally but (virtually) adiabatically

Performance of photovoltaic (PV) module is greatly dependent on the solar irradiance, operating temperature, and shading. Solar irradiance can have a significant impact on power output of PV module and energy yield. In this paper, a maximum PV power which can be obtain in Ramadi city (100km west of Baghdad) is practically analyzed. The analysis is based on real irradiance values obtained as the first time by using Soly2 sun tracker device. Proper and adequate information on solar radiation and its components at a given location is very essential in the design of solar energy systems. The solar irradiance data in Ramadi city were analyzed based on the first three months of 2013. The solar irradiance data are measured on earth's surface in the campus area of Anbar University. Actual average data readings were taken from the data logger of sun tracker system, which sets to save the average readings for each two minutes and based on reading in each one second. The data are analyzed from January to the end of March-2013. Maximum daily readings and monthly average readings of solar irradiance have been analyzed to optimize the output of photovoltaic solar modules. The results show that the system sizing of PV can be reduced by 12.5% if a tracking system is used instead of fixed orientation of PV modules.

The maximum transportable beam power is a critical issue in selecting the most favorable approach to generating ignition pulses for inertial fusion with high energy accelerators. Maschke and Courant have put forward expressions for the limits on transport power for quadrupole and solenoidal channels. Included in a more general way is the self consistent effect of space charge defocusing on the power limit. The results show that no limits on transmitted power exist in principal. In general, quadrupole transport magnets appear superior to solenoids except for transport of very low energy and highly charged particles. Longitudinal space charge effects are very significant for transport of intense beams

In this paper, an approximate curve fitting method for photovoltaic modules is presented. The operation is based on solving a simple solar cell electrical model by a microcontroller in real time. Only four voltage and current coordinates are needed to obtain the solar module parameters and set its operation at maximumpower in any conditions of illumination and temperature. Despite its simplicity, this method is suitable for low cost real time applications, as control loop reference generator in photovoltaic maximumpower point circuits. The theory that supports the estimator together with simulations and experimental results are presented. (author)

A method to maintain RF oscillation by using many Marx generators was proposed and studied experimentally. Many charging circuits were connected to an oscillator circuit, and successive pulsed charging was made. This successive charging amplified and maintained the RF oscillation. The use of vacuum gaps and high power silicon diodes improved the characteristics of RF current cut-off of the circuit. The efficiency of the pulsed charging from Marx generators to a condenser was theoretically investigated. The theoretical result showed the maximum efficiency of 0.98. The practical efficiency obtained by using a proposed circuit with a high power oscillator was in the range 0.50 to 0.56. The obtained effective output power of the RF pulses was 11 MW. The maximum holding time of the RF pulses was about 21 microsecond. (Kato, T.)

...) Maximum engine power for an engine family is generally the weighted average value of maximum engine power... engine family's maximum engine power apply in the following circumstances: (1) For outboard or personal... value for maximum engine power from all the different configurations within the engine family to...

A series of articles offers answers to questions on the environmental consequences and impact on man of the powergeneration industry. Subjects discussed in detail include: (i) acid rain and climate change and how the generators of electricity have been expected to play a role disproportionate to their deleterious contributions in improving the situation; (ii) recently adopted air quality management approaches with regard to airborne emissions from power stations and motor vehicles; (iii) the evolution of the UK power industry towards sustainability through considerations for the environment and use of resources in a liberalised market; (iv) the Best Practicable Environmental Option approach to the design and siting of power stations; (v) the environmental impact of nuclear powergeneration and (vi) electromagnetic fields and the possible effects on man of transmitting electricity in overhead power lines

Oceans, and particularly waves, offer a huge potential for energy harnessing all over the world. Nevertheless, the performance of current energy converters does not yet allow us to use the wave energy efficiently. However, new control techniques can improve the efficiency of energy converters. In this sense, the plant sensors play a key role within the control scheme, as necessary tools for parameter measuring and monitoring that are then used as control input variables to the feedback loop. Therefore, the aim of this work is to manage the rotational speed control loop in order to optimize the output power. With the help of outward looking sensors, a MaximumPower Point Tracking (MPPT) technique is employed to maximize the system efficiency. Then, the control decisions are based on the pressure drop measured by pressure sensors located along the turbine. A complete wave-to-wire model is developed so as to validate the performance of the proposed control method. For this purpose, a novel sensor-based flow controller is implemented based on the different measured signals. Thus, the performance of the proposed controller has been analyzed and compared with a case of uncontrolled plant. The simulations demonstrate that the flow control-based MPPT strategy is able to increase the output power, and they confirm both the viability and goodness. PMID:29439408

Oceans, and particularly waves, offer a huge potential for energy harnessing all over the world. Nevertheless, the performance of current energy converters does not yet allow us to use the wave energy efficiently. However, new control techniques can improve the efficiency of energy converters. In this sense, the plant sensors play a key role within the control scheme, as necessary tools for parameter measuring and monitoring that are then used as control input variables to the feedback loop. Therefore, the aim of this work is to manage the rotational speed control loop in order to optimize the output power. With the help of outward looking sensors, a MaximumPower Point Tracking (MPPT) technique is employed to maximize the system efficiency. Then, the control decisions are based on the pressure drop measured by pressure sensors located along the turbine. A complete wave-to-wire model is developed so as to validate the performance of the proposed control method. For this purpose, a novel sensor-based flow controller is implemented based on the different measured signals. Thus, the performance of the proposed controller has been analyzed and compared with a case of uncontrolled plant. The simulations demonstrate that the flow control-based MPPT strategy is able to increase the output power, and they confirm both the viability and goodness.

This paper outlines the main characteristics of powergeneration in Southern Africa, in terms of primary energy resources, existing and projected power supply and demand, types and location of power plants, regional integration, and environmental management aspects. Various options for future development of powergeneration are presented as part of an overall integrated resource planning (IRP) process for the power industry. These include coal and natural gas based options, hydro power and other renewable energy, and nuclear power plants. A specific option, the pebble bed modular reactor (PBMR), under development by Eskom Enterprises and other international and local partners, is described in terms of overall design parameters, inherent safety features, economics and environmental aspects. Included is a high level discussion on the selection of materials for the design of this PBMR plant, an advanced design version of a high temperature gas reactor (HTGR). (orig.)

In this paper, performance analysis and comparison based on the maximumpower and maximumpower density conditions have been conducted for an Atkinson cycle coupled to variable temperature heat reservoirs. The Atkinson cycle is internally reversible but externally irreversible, since there is external irreversibility of heat transfer during the processes of constant volume heat addition and constant pressure heat rejection. This study is based purely on classical thermodynamic analysis methodology. It should be especially emphasized that all the results and conclusions are based on classical thermodynamics. The power density, defined as the ratio of power output to maximum specific volume in the cycle, is taken as the optimization objective because it considers the effects of engine size as related to investment cost. The results show that an engine design based on maximumpower density with constant effectiveness of the hot and cold side heat exchangers or constant inlet temperature ratio of the heat reservoirs will have smaller size but higher efficiency, compression ratio, expansion ratio and maximum temperature than one based on maximumpower. From the view points of engine size and thermal efficiency, an engine design based on maximumpower density is better than one based on maximumpower conditions. However, due to the higher compression ratio and maximum temperature in the cycle, an engine design based on maximumpower density conditions requires tougher materials for engine construction than one based on maximumpower conditions

Nuclear PowerGeneration focuses on the use of nuclear reactors as heat sources for electricity generation. This volume explains how nuclear energy can be harnessed to produce power by discussing the fundamental physical facts and the properties of matter underlying the operation of a reactor. This book is comprised of five chapters and opens with an overview of nuclear physics, first by considering the structure of matter and basic physical concepts such as atomic structure and nuclear reactions. The second chapter deals with the requirements of a reactor as a heat source, along with the diff

The proceedings contain 21 papers, of which 7 are devoted to nuclear powergeneration. They are concerned with the working environment in the controlled areas of the Bohunice nuclear power plant, the unsuitable design of the control rooms with respect to reliability and safety of operation of the nuclear power plant, optimization of the man-working conditions relation, operation of transport facilities, refuelling and fuel element inspection, the human factor and the probabilityy assessment of the nuclear power plant operating safety, a proposal to establish a universal ergonometric programme for the electric power distribution system, and physical factors in the ergonometric analysis of the working environment. (J.B.)

Since the energy crisis, powergeneration from waste wood has become increasingly important. The most profitable way to use waste wood in woodworking plants with an annual production of 100 to 150,000 m/sup 3/ solid measure of wood chips and bark is by combustion and thermal energy recovery. In plants with an annual production of 10,000 m/sup 3/ solid measure of wood chips and bark, electric powergeneration is a suitable application.

A simplified calculational procedure for the estimation of nuclear powergeneration cost is outlined. The report contains a discussion of the various components of powergeneration cost and basic equations for calculating that cost. An example calculation is given. The basis of the fixed-charge rate, the derivation of the levelized fuel cycle cost equation, and the heavy water charge rate are included as appendixes

The operating point of a photovoltaic generator that is connected to a load is determined by the intersection point of its characteristic curves. In general, this point is not the same as the generator's maximumpower point. This difference means losses in the system performance. DC/DC converters together with maximumpower point tracking systems (MPPT) are used to avoid these losses. Different algorithms have been proposed for maximumpower point tracking. Nevertheless, the choice of the configuration of the right converter has not been studied so widely, although this choice, as demonstrated in this work, has an important influence in the optimum performance of the photovoltaic system. In this article, we conduct a study of the three basic topologies of DC/DC converters with resistive load connected to photovoltaic modules. This article demonstrates that there is a limitation in the system's performance according to the type of converter used. Two fundamental conclusions are derived from this study: (1) the buck-boost DC/DC converter topology is the only one which allows the follow-up of the PV module maximumpower point regardless of temperature, irradiance and connected load and (2) the connection of a buck-boost DC/DC converter in a photovoltaic facility to the panel output could be a good practice to improve performance. (author)

MaximumPower Point Tracking (MPPT) has played a vital role to enhance the efficiency of solar photovoltaic (PV) powergeneration under varying atmospheric temperature and solar irradiation. However, it is hard to track the maximumpower point using conventional linear controllers due to the natural inheritance of nonlinear I-V and P-V characteristics of solar PV systems. Fuzzy Logic Controller (FLC) is suitable for nonlinear system control applications and eliminating oscillations, circuit c...

Full Text Available The power converter is one of the essential elements for effective use of renewable power sources. This paper focuses on the development of a circuit simulation model for maximumpower point tracking (MPPT evaluation of solar power that involves using different buck-boost power converter topologies; including SEPIC, Zeta, and four-switch type buck-boost DC/DC converters. The circuit simulation model mainly includes three subsystems: a PV model; a buck-boost converter-based MPPT system; and a fuzzy logic MPPT controller. Dynamic analyses of the current-fed buck-boost converter systems are conducted and results are presented in the paper. The maximumpower point tracking function is achieved through appropriate control of the power switches of the power converter. A fuzzy logic controller is developed to perform the MPPT function for obtaining maximumpower from the PV panel. The MATLAB-based Simulink piecewise linear electric circuit simulation tool is used to verify the complete circuit simulation model.

A well engineered renewable remote energy system, utilizing the principal of MaximumPower Point Tracking (MPPT) can improve cost effectiveness, has a higher reliability and can improve the quality of life in remote areas. A high-efficient power electronic converter, for converting the output voltage of a solar panel, or wind generator, to the required DC battery bus voltage has been realized. The converter is controlled to track the maximumpower point of the input source under varying input and output parameters. Maximumpower point tracking for relative small systems is achieved by maximization of the output current in a battery charging regulator, using an optimized hill-climbing, inexpensive microprocessor based algorithm. Through practical field measurements it is shown that a minimum input source saving of between 15 and 25% on 3-5 kWh/day systems can easily be achieved. A total cost saving of at least 10-15% on the capital cost of these systems are achievable for relative small rating Remote Area Power Supply (RAPS) systems. The advantages at large temperature variations and high power rated systems are much higher. Other advantages include optimal sizing and system monitor and control. (author).

This paper proposes that wind generator system is operated by using wind collection equipment and MaximumPower Point Tracking more and more high-efficient. As an example of the utility, it was proposed that it was used for the regeneration of electric vehicle. The efficiency upgrading of electric vehicle can be expect by introducing in addition, proposing system with the conventional regeneration. The field experiment was carried out in order to measure the effect. Regeneration energy by pro...

This paper analyses the operation of the wind turbine, WT, in the maximumpower point, MPP, by linking the load of the Permanent Magnet Synchronous Generator, PMSG, with the wind speed value. The load control methods at wind power systems aiming an optimum performance in terms of energy are based on the fact that the energy captured by the wind turbine significantly depends on the mechanical angular speed of the wind turbine. The presented control method consists in determining the optimal mechanical angular speed, ωOPTIM, using an auxiliary low power wind turbine, WTAUX, operating without load, at maximum angular velocity, ωMAX. The method relies on the fact that the ratio ωOPTIM/ωMAX has a constant value for a given wind turbine and does not depend on the time variation of the wind speed values.

Highlights: • Direct MPP finding by parallelogram constructed from geometry of I–V curve of cell. • Exact values of V and P at MPP obtained by Lagrangian interpolation exploration. • Extensive use of Lagrangian interpolation for implementation of proposed method. • Method programming on C platform with minimum computational burden. - Abstract: It is important to drive solar photovoltaic (PV) system to its utmost capacity using maximumpower point (MPP) tracking algorithms. This paper presents a direct MPP prediction method for a PV system considering the geometry of the I–V characteristic of a solar cell and a module. In the first step, known as parallelogram exploration (PGE), the MPP is determined from a parallelogram constructed using the open circuit (OC) and the short circuit (SC) points of the I–V characteristic and Lagrangian interpolation. In the second step, accurate values of voltage and power at the MPP, defined as V mp and P mp respectively, are decided by the Lagrangian interpolation formula, known as the Lagrangian interpolation exploration (LIE). Specifically, this method works with a few (V, I) data points instead most of the MPP algorithms work with (P, V) data points. The performance of the method is examined by several PV technologies including silicon, copper indium gallium selenide (CIGS), copper zinc tin sulphide selenide (CZTSSe), organic, dye sensitized solar cell (DSSC) and organic tandem cells’ data previously reported in literatures. The effectiveness of the method is tested experimentally for a few silicon cells’ I–V characteristics considering variation in the light intensity and the temperature. At last, the method is also employed for a 10 W silicon module tested in the field. To testify the preciseness of the method, an absolute value of the derivative of power (P) with respect to voltage (V) defined as (dP/dV) is evaluated and plotted against V. The method estimates the MPP parameters with high accuracy for any

This report focuses mainly on developments to improve the performance of coal-based powergeneration technologies, which should be a priority -- particularly if carbon capture and storage takes longer to become established than currently projected. A close look is taken of the major ongoing developments in process technology, plant equipment, instrumentation and control. Coal is an important source of energy for the world, particularly for powergeneration. To meet the growth in demand for energy over the past decade, the contribution from coal has exceeded that of any other energy source. Additionally, coal has contributed almost half of total growth in electricity over the past decade. As a result, CO2 emissions from coal-fired powergeneration have increased markedly and continue to rise. More than 70% of CO2 emissions that arise from powergeneration are attributed to coal. To play its role in a sustainable energy future, its environmental footprint must be reduced; using coal more efficiently is an important first step. Beyond efficiency improvement, carbon capture and storage (CCS) must be deployed to make deep cuts in CO2 emissions. The need for energy and the economics of producing and supplying it to the end-user are central considerations in power plant construction and operation. Economic and regulatory conditions must be made consistent with the ambition to achieve higher efficiencies and lower emissions. In essence, clean coal technologies must be more widely deployed.

PowerGeneration from Solid Fuels introduces the different technologies to produce heat and power from solid fossil (hard coal, brown coal) and renewable (biomass, waste) fuels, such as combustion and gasification, steam power plants and combined cycles etc. The book discusses technologies with regard to their efficiency, emissions, operational behavior, residues and costs. Besides proven state of the art processes, the focus is on the potential of new technologies currently under development or demonstration. The main motivation of the book is to explain the technical possibilities for reduci

My generation was labeled by Russian mass media as generation 'Next.' My technical education is above average. My current position is as a mechanical engineer in the leading research and development institute for Russian nuclear engineering for peaceful applications. It is noteworthy to point out that many of our developments were really first-of-a-kind in the history of engineering. However, it is difficult to grasp the importance of these accomplishments, especially since the progress of nuclear technologies is at a standstill. Can generation 'Next' be independent in their attitude towards nuclear power or shall we rely on the opinions of elder colleagues in our industry? (authors)

This paper proposes and implements a thermoelectric waste heat energy recovery system for internal combustion engine automobiles, including gasoline vehicles and hybrid electric vehicles. The key is to directly convert the heat energy from automotive waste heat to electrical energy using a thermoelectric generator, which is then regulated by a DC-DC Cuk converter to charge a battery using maximumpower point tracking. Hence, the electrical power stored in the battery can be maximized. Both analysis and experimental results demonstrate that the proposed system can work well under different working conditions, and is promising for automotive industry.

Critical stand-by power applications, such as in a nuclear plant, or radio support stations, demand exacting guidelines for positive start, rapid acceleration, load acceptance with minimum voltage drop, and quick recovery to rated voltage. The design of medium-speed turbocharged and intercooled diesel-engine-generator for this purpose is considered. Selection of the diesel engine, size, and number of units, from the standpoint of cost, favors minimum number of units with maximum horsepower capability. Four-cycle diesels are available in 16 to 20 cyinders V-configurations, with 200 BMEP (brake mean-effective pressure) continuous and 250 BMEP peaking

The cell has optimum operating point to be able to get maximumpower. To obtain MaximumPower from photovoltaic array, photovoltaic power system usually requires MaximumPower Point Tracking (MPPT) controller. This paper provides a small power photovoltaic control system based on fuzzy control with FPGA technology design and implementation for MPPT. The system composed of photovoltaic module, buck converter and the fuzzy logic controller implemented on FPGA for controlling on/off time of MOSF...

With the high voltage intelligent substation developing in a pretty high speed, more and more artificial intelligent techniques have been incorporated into the power devices to meet the automation needs. For the sake of the line maintenance staff’s safety, the high voltage isolating switch draws great attention among the most important power devices because of its capability of connecting and disconnecting the high voltage circuit. However, due to the very high level voltage of the high voltage isolating switch’s working environment, the power supply system of the surveillance devices could suffer from great electromagnetic interference. Laser power beaming exhibits its merits in such situation because it can provide steady power from a distance despite the day or the night. Then the energy conversion efficiency arises as a new concern. To make as much use of the laser power as possible, our work mainly focuses on extracting maximumpower from the photovoltaic (PV) panel. In this paper, we proposed a neural network based algorithm which relates both the intrinsic and the extrinsic features of the PV panel to the proportion of the voltage at the maximumpower point (MPP) to the open circuit voltage of the PV panel. Simulations and experiments were carried out to verify the validness of our algorithm.

This paper proposes the sensorless output power maximization control of the wind generation system. A permanent magnet synchronous generator (PMSG) is used as a variable speed generator in the proposed system. The generator torque is suitably controlled according to the generator speed and thus the power from a wind turbine settles down on the maximumpower point by the proposed MPPT control method, where the information of wind velocity is not required. Moreover, the maximum available generatedpower is obtained by the optimum current vector control. The current vector of PMSG is optimally controlled according to the generator speed and the required torque in order to minimize the losses of PMSG considering the voltage and current constraints. The proposed wind powergeneration system can be achieved without mechanical sensors such as a wind velocity detector and a position sensor. Several experimental results show the effectiveness of the proposed control method.

In the context of renewable energy, the maximumpower point tracker (MPPT) is often used to increase the solar power efficiency, taking into account the randomness and volatility of solar energy due to changes in temperature and photovoltaic. In all MPPT techniques, perturb & observe and incremental conductance are widely used in MPPT controllers, because of their simplicity and ease of operation. According to the internal structure of the photovoltaic cell and the output volt-ampere characteristic, this paper established the circuit model and establishes the dynamic simulation model in Matlab/Simulink with the preparation of the s function. The perturb & observe MPPT method and the incremental conductance MPPT method were analyzed and compared by the theoretical analysis and digital simulation. The simulation results have shown that the system with INC MPPT method has better dynamic performance and improves the output power of photovoltaic powergeneration.

Full Text Available This paper proposes a technique of intelligent control to track the maximumpower point (MPPT of a photovoltaic system . The PV system is non-linear and it is exposed to external perturbations like temperature and solar irradiation. Fuzzy logic control is known for its stability and robustness. FLC is adopted in this work for the improvement and optimization of control performance of a photovoltaic system. Another technique called perturb and observe (P & O is studied and compared with the FLC technique. The PV system is constituted of a photovoltaic panel (PV, a DC-DC converter (Boost and a battery like a load. The simulation results are developed in MATLAB / Simulink software. The results show that the controller based on fuzzy logic is better and faster than the conventional controller perturb and observe (P & O and gives a good maximumpower of a photovoltaic generator under different changes of weather conditions.

A number of current and prospective power plant concepts were investigated to evaluate their potential to serve as the basis of the next generation geothermal power plant (NGGPP). The NGGPP has been envisaged as a power plant that would be more cost competitive (than current geothermal power plants) with fossil fuel power plants, would efficiently use resources and mitigate the risk of reservoir under-performance, and minimize or eliminate emission of pollutants and consumption of surface and ground water. Power plant concepts were analyzed using resource characteristics at ten different geothermal sites located in the western United States. Concepts were developed into viable power plant processes, capital costs were estimated and levelized busbar costs determined. Thus, the study results should be considered as useful indicators of the commercial viability of the various power plants concepts that were investigated. Broadly, the different power plant concepts that were analyzed in this study fall into the following categories: commercial binary and flash plants, advanced binary plants, advanced flash plants, flash/binary hybrid plants, and fossil/geothed hybrid plants. Commercial binary plants were evaluated using commercial isobutane as a working fluid; both air-cooling and water-cooling were considered. Advanced binary concepts included cycles using synchronous turbine-generators, cycles with metastable expansion, and cycles utilizing mixtures as working fluids. Dual flash steam plants were used as the model for the commercial flash cycle. The following advanced flash concepts were examined: dual flash with rotary separator turbine, dual flash with steam reheater, dual flash with hot water turbine, and subatmospheric flash. Both dual flash and binary cycles were combined with other cycles to develop a number of hybrid cycles: dual flash binary bottoming cycle, dual flash backpressure turbine binary cycle, dual flash gas turbine cycle, and binary gas turbine

This article develops a model of the innovation-adoption decision. The model allows the economic situation of a utility and its perception of uncertainty associated with an innovation to affect the probability of adopting it. This model is useful when uncertainties affecting decisions about adoption persist throughout the diffusion process, thereby making the usual adoption model implicit in rate-of-diffusion studies inappropriate. An empirical test of the model finds that firm size, power pool size, and selected aspects of uncertainty about the innovation are significant predictors of US utility companies' decisions on whether or not to adopt nuclear powergeneration. 17 references, 2 tables

Highlights: • Create a simple, easy of implement and accurate V_M_P_P estimator. • Stability analysis of the proposed system based on the Lyapunov’s theory. • A comparative study versus P&O, highlight SMC good performances. • Construct a new PS-SMC algorithm to include the partial shadow case. • Experimental validation of the SMC MPP tracker. - Abstract: This paper presents a photovoltaic (PV) system with a maximumpower point tracking (MPPT) facility. The goal of this work is to maximize power extraction from the photovoltaic generator (PVG). This goal is achieved using a sliding mode controller (SMC) that drives a boost converter connected between the PVG and the load. The system is modeled and tested under MATLAB/SIMULINK environment. In simulation, the sliding mode controller offers fast and accurate convergence to the maximumpower operating point that outperforms the well-known perturbation and observation method (P&O). The sliding mode controller performance is evaluated during steady-state, against load varying and panel partial shadow (PS) disturbances. To confirm the above conclusion, a practical implementation of the maximumpower point tracker based sliding mode controller on a hardware setup is performed on a dSPACE real time digital control platform. The data acquisition and the control system are conducted all around dSPACE 1104 controller board and its RTI environment. The experimental results demonstrate the validity of the proposed control scheme over a stand-alone real photovoltaic system.

Highlights: • We propose an adaptive maximumpower point tracking (MPPT) approach for PV systems. • Transient and steady state performances in tracking process are improved. • The proposed MPPT can automatically tune tracking step size along a P–V curve. • A PSO algorithm is used to determine the weighting values of extension theory. - Abstract: The aim of this work is to present an adaptive maximumpower point tracking (MPPT) approach for photovoltaic (PV) powergeneration system. Integrating the extension theory as well as the conventional perturb and observe method, an maximumpower point (MPP) tracker is made able to automatically tune tracking step size by way of the category recognition along a P–V characteristic curve. Accordingly, the transient and steady state performances in tracking process are improved. Furthermore, an optimization approach is proposed on the basis of a particle swarm optimization (PSO) algorithm for the complexity reduction in the determination of weighting values. At the end of this work, a simulated improvement in the tracking performance is experimentally validated by an MPP tracker with a programmable system-on-chip (PSoC) based controller

Communicating the benefits of nuclear powergeneration, although essential, is unlikely to be sufficient by itself to counter the misconceptions which hinder the adoption of this technology, viz: that it is unsafe, generates intractable waste, facilitates the proliferation of nuclear weapons, etc. Underlying most of these objections is the fear of radiation, engendered by misunderstandings of the effects of exposure - not the actual risks of radiation exposure themselves. Unfortunately, some aspects of current radiation protection practices promote the misconception that there is no safe dose. A prime purpose of communications from the nuclear industry should be to dispel these misconceptions. (author)

The Defense Waste Processing Facility (DWPF) at the Savannah River Site is developing for implementation a flowsheet with a new reductant to replace formic acid. Glycolic acid has been tested over the past several years and found to effectively replace the function of formic acid in the DWPF chemical process. The nitric-glycolic flowsheet reduces mercury, significantly lowers the chemical generation of hydrogen and ammonia, allows purge reduction in the Sludge Receipt and Adjustment Tank (SRAT), stabilizes the pH and chemistry in the SRAT and the Slurry Mix Evaporator (SME), allows for effective adjustment of the SRAT/SME rheology, and is favorable with respect to melter flammability. The objective of this work was to perform DWPF Chemical Process Cell (CPC) testing at conditions that would bound the catalytic hydrogen production for the nitric-glycolic flowsheet.

The first part of the 2003 study of reference costs for powergeneration has been completed. It was carried out by the General Directorate for Energy and Raw Materials (DGEMP) of the French Ministry of the Economy, Finance and Industry, with the collaboration of power-plant operators, construction firms and many other experts. A Review Committee of experts including economists (Forecasting Department, French Planning Office), qualified public figures, representatives of power-plant construction firms and operators, and non-governmental organization (NGO) experts, was consulted in the final phase. The study examines the costs of powergenerated by different methods (i.e. nuclear and fossil-fuel [gas-, coal-, and oil-fired] power plants) in the context of an industrial operation beginning in the year 2015. - The second part of the study relating to decentralized production methods (wind, photovoltaic, combined heat and power) is still in progress and will be presented at the beginning of next year. - 1. Study approach: The study is undertaken mainly from an investor's perspective and uses an 8% discount rate to evaluate the expenses and receipts from different years. In addition, the investment costs are considered explicitly in terms of interest during construction. - 2. Plant operating on a full-time basis (year-round): The following graph illustrates the main conclusions of the study for an effective operating period of 8000 hours. It can be seen that nuclear is more competitive than the other production methods for a year-round operation with an 8% discount rate applied to expenses. This competitiveness is even better if the costs related to greenhouse-gas (CO 2 ) emission are taken into account in estimating the MWh cost price. Integrating the costs resulting from CO 2 emissions by non-nuclear fuels (gas, coal), which will be compulsory as of 2004 with the transposition of European directives, increases the total cost per MWh of these powergeneration methods

A maximumpower point tracking (MPPT) scheme by tracking the open-circuit voltage from a piezoelectric energy harvester using a differentiator is presented in this paper. The MPPT controller is implemented by using a low-power analogue differentiator and comparators without the need of a sensing circuitry and a power hungry controller. This proposed MPPT circuit is used to control a buck converter which serves as a power management module in conjunction with a full-wave bridge diode rectifier. Performance of this MPPT control scheme is verified by using the prototyped circuit to track the maximumpower point of a macro-fiber composite (MFC) as the piezoelectric energy harvester. The MFC was bonded on a composite material and the whole specimen was subjected to various strain levels at frequency from 10 to 100 Hz. Experimental results showed that the implemented full analogue MPPT controller has a tracking efficiency between 81% and 98.66% independent of the load, and consumes an average power of 3.187 μW at 3 V during operation.

Traditional powergeneration systems using thermoelectric powergenerators are designed to operate most efficiently for a single operating condition. The present invention provides a powergeneration system in which the characteristics of the thermoelectrics, the flow of the thermal power, and the operational characteristics of the powergenerator are monitored and controlled such that higher operation efficiencies and/or higher output powers can be maintained with variably thermal power input. Such a system is particularly beneficial in variable thermal power source systems, such as recovering power from the waste heat generated in the exhaust of combustion engines.

Based on the blade element momentum (BEM) theory, the power coefficient of a wind turbine can be expressed in function of local tip speed ratio and lift-drag ratio. By taking the power coefficient in a predefined range of angle of attack as the final design objective and combining with an airfoil...

Prior to independence most industries had their own captive powergeneration. Steam was generated in own medium/low pressure boilers and passed through extraction condensing turbines for powergeneration. Extraction steam was used for process. With cheaper power made available in Nehru era by undertaking large hydro power schemes, captive powergeneration in industries was almost abandoned except in sugar and large paper factories, which were high consumers of steam. (author)

The OPG Review Committee was formed by the Ontario Ministry of Energy to provide recommendations and advice on the future role of Ontario PowerGeneration Inc. (OPG) in the electricity sector. This report describes the future structure of OPG with reference to the appropriate corporate governance and senior management structure. It also discusses the potential refurbishing of the Pickering A nuclear generating Units 1, 2 and 3. The electricity system in Ontario is becoming increasingly fragile. The province relies heavily on electricity imports and the transmission system is being pushed to near capacity. Three nuclear generating units are out of service. The problems can be attributed to the fact that the electricity sector has been subjected to unpredictable policy changes for more than a decade, and that the largest electricity generator (OPG) has not been well governed. OPG has had frequent senior management change, accountability has been weak, and cost overruns have delayed the return to service of the Pickering nuclear power Unit 4. It was noted that the generating assets owned and operated by OPG are capable of providing more than 70 per cent of Ontario's electricity supply. Decisive action is needed now to avoid a potential supply shortage of about 5,000 to 7,000 megawatts by 2007. In its current state, OPG risks becoming a burden on ratepayers. Forty recommendations were presented, some of which suggest that OPG should become a rate-regulated commercial utility focused on running and maintaining its core generating assets. This would require that the government act as a shareholder, and the company operate like a commercial business. It was also emphasized that the market must be allowed to bring in new players. refs., tabs., figs

This paper presents a development and implementation of a PC-based maximumpower point tracker (MPPT) for PV system using neural networks (NN). The system consists of a PV module via a MPPT supplying a dc motor that drives an air fan. The control algorithm is developed to use the artificial NN for detecting the optimal operating point under different operating conditions, then the control action gives the driving signals to the MPPT. A PC is used for data acquisition, running the control algorithm, data storage, as well as data display and analysis. The system has been implemented and tested under various operating conditions. The experimental results showed that the PV system with MPPT always tracks the peak power point of the PV module under various operating conditions. The MPPT transmits about 97% of the actual maximumpowergenerated by the PV module. The MPPT not only increases the power from the PV module to the load, but also maintains longer operating periods for the PV system. The air velocity and the air mass flow rate of the mechanical load are increased considerably, due to the increase of the PV system power. It is also found that the increase in the output energy due to using the MPPT is about 45.2% for a clear sunny day. (Author)

induction generator (SCIG) is used to illustrate the generator control system for a variable‐speed WECS. The chapter also presents case studies have been carried out to verify the developed adaptive controller for WECSs. WECSs are non‐linear systems with parameter uncertainties and which are subject...... to disturbances, in the form of non‐linear and unmodeled aerodynamics....

Nuclear power plants began to be built in Europe in the latter half of 1960. 146 plants are operating and generating about 33% of total power in 2002. France is top of Europe and operating 59 plants, which generate about 75% of powergeneration in the country. Germany is second and 30%. England is third and 30%. However, Germany decided not to build new atomic power plant in 2000. Movement of non-nuclear powergeneration is decreasing in Belgium and Switzerland. The liberalization of powergeneration decreased the wholesale price and BE Company in England was financial difficulties. New nuclear powergeneration is planning in Finland and France. (S.Y.)

Full Text Available The issue paper is to present renewable energy sources insisting mainly on wind energy. This source is analyzed in the context of Romania in particular and the EU in general. A turbine with horizontal axis is usually coupled with vessel power systems. Wind energy knows an increased growth rate. At the end of the paper are presented possible structure of coupled a wind to power systems.

Full Text Available A new simple fuzzy method used for tracking the maximumpower point tracker (MPPT for photovoltaic systems is proposed. The input parameters and duty cycle D are used to generate the optimal MPPT under different operating conditions, The photovoltaic system simulated and constructed by photovoltaic arrays, a DC/DC boost converter, a fuzzy MPPT control and a resistive load, The Fuzzy control law designed and the results in a simulation platform will be presented and compare to Perturbation and observation (P&O controller.

This paper presents modeling and simulation of three level Boost DC-DC converter in Wind Energy Conversion System (WECS). Three-level Boost converter has significant advantage compared to conventional Boost. A maximumpower point tracking (MPPT) method for a variable speed wind turbine using permanent magnet synchronous generator (PMSG) is also presented. Simulation of three-level Boost converter topology with Perturb and Observe algorithm and Fuzzy Logic Control is implemented in MATLAB/SIMULINK. Results of this simulation show that the system with MPPT using fuzzy logic controller has better performance to the Perturb and Observe algorithm: fast response under changing conditions and small oscillation.

Disposing of radioactive wastes from nuclear power plants has become one of the most important issues facing the nuclear industry. In a new concept, called a radioisotope photovoltaic generator, a portion of this waste would be used in conjunction with a scintillation material to produce light, with subsequent conversion into electricity via photovoltaic cells. Three types of scintillators and two types of silicon cells were tested in six combinations using 32 P as the radioisotope. The highest system efficiency, determined to be 0.5% when the light intensity was normalized to 100 mW/cm 2 , was obtained using a CsI crystal scintillator and a Helios photovoltaic cell

Designs for flexible, high-power-density, remote irradiation systems are presented. Applications include industrial infrared heating such as in semiconductor processing, alternatives to laser light for certain medical procedures, and general remote high-brightness lighting. The high power densities in herent to the small active radiating regions of conventional metal-halide, halogen, xenon, microwave-sulfur, and related lamps can be restored with nonimaging concentrators with little loss of power. These high fluxlevels can then be transported at high transmissivity with light channels such as optical fibers or lightpipes, and reshaped into luminaires that can deliver prescribed angular and spatial flux distributions onto desired targets. Details for nominally two- and three-dimensional systems are developed, along with estimates ofoptical performance.

Full Text Available Photovoltaic panels have a non-linear current-voltage characteristics to produce the maximumpower at only one point called the maximumpower point. In the case of the uniform illumination a single solar panel shows only one maximumpower, which is also the global maximumpower point. In the case an irregularly illuminated photovoltaic panel many local maxima on the power-voltage curve can be observed and only one of them is the global maximum. The proposed algorithm detects whether a solar panel is in the uniform insolation conditions. Then an appropriate strategy of tracking the maximumpower point is taken using a decision algorithm. The proposed method is simulated in the environment created by the authors, which allows to stimulate photovoltaic panels in real conditions of lighting, temperature and shading.

Studies on the consumption of energy by an ozone generator with various constructions electrodes of dielectric barrier discharge plasma (DBDP) reactor has been carried out. This research was done to get the configuration of the reactor, that is capable to produce high ozone concentrations with low energy consumption. BDBP reactors were constructed by spiral- cylindrical configuration, plasma ozone was generated by high voltage AC voltage up to 25 kV and maximum frequency of 23 kHz. The reactor consists of an active electrode in the form of a spiral-shaped with variation diameter Dc, and it was made by using copper wire with diameter Dw. In this research, we variated number of loops coil windings N as well as Dc and Dw. Ozone concentrations greater when the wire's diameter Dw and the diameter of the coil windings applied was greater. We found that impedance greater will minimize the concentration of ozone, in contrary to the greater capacitance will increase the concentration of ozone. The ozone concentrations increase with augmenting of power. Maximumpower is effective at DBD reactor spiral-cylinder is on the Dc = 20 mm, Dw = 1.2 mm, and the number of coil windings N = 10 loops with the resulting concentration is greater than 20 ppm and it consumes energy of 177.60 watts (paper)

An efficient maximumpower point tracker (MPPT) has been developed and can be used with a photovoltaic (PV) array and a load which requires lower voltage than the PV array voltage to be operated. The MPPT makes the PV array to operate at maximumpower point (MPP) under all insolation and temperature, which ensures the maximum amount of available PV power to be delivered to the load. The performance of the MPPT has been studied under different insolation levels.

Full Text Available This paper gives a review of the most efficient algorithms designed to track the maximumpower point (MPP for catching the maximum wind power by a variable speed wind turbine (VSWT. We then design a new maximumpower point tracking (MPPT algorithm using the Variable Structure Automatic Systems approach (VSAS. The proposed approachleads efficient algorithms as shown in this paper by the analysis and simulations.

A powergeneration system is described, comprising: a gaseous core nuclear reactor; means for passing helium through the reactor, the helium being excited and forming alpha particles by high frequency radiation from the core of the gaseous core nuclear reactor; a reaction chamber; means for coupling chlorine and hydrogen to the reaction chamber, the helium and alpha particles energizing the chlorine and hydrogen to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for coupling the helium back to the gaseous core nuclear reactor; and means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, to be coupled back to the reaction chamber in a closed loop. The patent also describes a powergeneration system comprising: a gaseous core nuclear reactor; means for passing hydrogen through the reactor, the hydrogen being excited by high frequency radiation from the core; means for coupling chlorine to a reaction chamber, the hydrogen energizing the chlorine in the chamber to form a high temperature, high pressure hydrogen chloride plasma; means for converting the plasma to electromechanical energy; means for disassociating the hydrogen chloride to form molecular hydrogen and chlorine, and means for coupling the hydrogen back to the gaseous core nuclear reactor in a closed loop

An electret powergenerator is developed using a new electret made of a charged parylene HT® thin-film polymer. Here, parylene HT® is a room-temperature chemical-vapor-deposited thin-film polymer that is MEMS and CMOS compatible. With corona charge implantation, the surface charge density of parylene HT® is measured as high as 3.69 mC m −2 . Moreover, it is found that, with annealing at 400 °C for 1 h before charge implantation, both the long-term stability and the high-temperature reliability of the electret are improved. For the generator, a new design of the stator/rotor is also developed. The new micro electret generator does not require any sophisticated gap-controlling structure such as tethers. With the conformal coating capability of parylene HT®, it is also feasible to have the electret on the rotors, which is made of either a piece of metal or an insulator. The maximumpower output, 17.98 µW, is obtained at 50 Hz with an external load of 80 MΩ. For low frequencies, the generator can harvest 7.7 µW at 10 Hz and 8.23 µW at 20 Hz

An analysis is given of the spatial distribution of fuel burnup and enrichment in a light-water lattice of given dimensions with slightly enriched uranium, at which the maximum output is achieved. It is based on the spatial solution of neutron flux using a one-group diffusion model in which linear dependence may be expected of the fission cross section and the material buckling parameter on the fuel burnup and enrichment. Two problem constraints are considered, i.e., the neutron flux value and the specific output value. For the former the optimum core configuration remains qualitatively unchanged for any reflector thickness, for the latter the cases of a reactor with and without reflector must be distinguished. (Z.M.)

Coal is the biggest single source of energy for electricity production and its share is growing. The efficiency of converting coal into electricity matters: more efficient power plants use less fuel and emit less climate-damaging carbon dioxide. This book explores how efficiency is measured and reported at coal-fired power plants. With many different methods used to express efficiency performance, it is often difficult to compare plants, even before accounting for any fixed constraints such as coal quality and cooling-water temperature. Practical guidelines are presented that allow the efficiency and emissions of any plant to be reported on a common basis and compared against best practice. A global database of plant performance is proposed that would allow under-performing plants to be identified for improvement. Armed with this information, policy makers would be in a better position to monitor and, if necessary, regulate how coal is used for powergeneration. The tools and techniques described will be of value to anyone with an interest in the more sustainable use of coal.

Full Text Available The difference between quantum isoenergetic process and quantum isothermal process comes from the violation of the law of equipartition of energy in the quantum regime. To reveal an important physical meaning of this fact, here we study a special type of quantum heat engine consisting of three processes: isoenergetic, isothermal and adiabatic processes. Therefore, this engine works between the energy and heat baths. Combining two engines of this kind, it is possible to realize the quantum Carnot engine. Furthermore, considering finite velocity of change of the potential shape, here an infinite square well with moving walls, the power output of the engine is discussed. It is found that the efficiency and power output are both closely dependent on the initial and final states of the quantum isothermal process. The performance of the engine cycle is shown to be optimized by control of the occupation probability of the ground state, which is determined by the temperature and the potential width. The relation between the efficiency and power output is also discussed.

One of the major challenges facing Ghana in her developmental efforts is the generation of adequate and affordable electricity to meet increasing demand. Problems with the dependency on hydro power has brought insecurity in electricity supply due to periodic droughts. Thermal power systems have been introduced into the electricity generation mix to complement the hydro power supply but there are problems associated with their use. The high price of crude oil on the international market has made them expensive to run and the supply of less expensive gas from Steps are being taken to run the thermal plants on less expensive gas from Nigeria has delayed due to conflicts in the Niger Delta region and other factors. The existing situation has therefore called for the diversification of the electricity generation mix so as to ensure energy security and affordable power supply. This paper presents the nuclear option as a suitable alternative energy source which can be used to address the energy supply problems facing the nation as well the steps being taken towards its introduction in the national energy mix. In addition, electricity demand projections using the MAED model as well as other studies are presented. The expected electricity demand of 350000 GWh (4000MWyr) in 2030, exceeds the total electricity supply capability of the existing hydropower system, untapped hydro resources and the maximum amount of gas that can be imported from Nigeria through the West Africa pipeline. Also presented is a technological assessment on the type of nuclear reactor to be used. The technological assessment which was done based on economics, grid size, technological maturity, passive safety and standardization of reactor design, indicate that a medium sized pressurized water reactor (i.e. a PWR with capacity 300MW to 700MW) is the most favourable type of reactor. In addition the challenges facing the implementation of the nuclear power programme in Ghana are presented. (author)

It is crucial to improve the photovoltaic (PV) system efficiency and to develop the reliability of PV generation control systems. There are two ways to increase the efficiency of PV powergeneration system. The first is to develop materials offering high conversion efficiency at low cost. The second is to operate PV systems optimally. However, the PV system can be optimally operated only at a specific output voltage and its output power fluctuates under intermittent weather conditions. Moreover, it is very difficult to test the performance of a maximum-power point tracking (MPPT) controller under the same weather condition during the development process and also the field testing is costly and time consuming. This paper presents a novel real-time simulation technique of PV generation system by using dSPACE real-time interface system. The proposed system includes Artificial Neural Network (ANN) and fuzzy logic controller scheme using polar information. This type of fuzzy logic rules is implemented for the first time to operate the PV module at optimum operating point. ANN is utilized to determine the optimum operating voltage for monocrystalline silicon, thin-film cadmium telluride and triple junction amorphous silicon solar cells. The verification of availability and stability of the proposed system through the real-time simulator shows that the proposed system can respond accurately for different scenarios and different solar cell technologies. (author)

Current problems of and future trends in coal-based powergeneration are discussed. The present situation is as follows: coal, oil and gas contribute to world fossil fuel resources 75%, 14%, and 11%, respectively, and if the current trend will continue, will be depleted in 240, 50, and 60 years, respectively; the maximum resource estimates (including resources that have not yet been discovered) are 50% higher for oil and 100% higher for gas, for coal such estimates have not been made. While the world prices of coal are expected to remain virtually constant, the prices of gas will probably increase to be twice as high in 2010. Thus, the role of coal may be higher in the next century than it is now, provided that due attention is paid to improving the efficiency of coal-fired power plants and reducing their adverse environmental effects. A comparison of economic data for coal-fired and gas-fired power plants is as follows: Investment cost (USD/kW): 1400, 800; fixed running cost (USD/kW.y): 33.67, 9.0; variable running cost (USD/kWh): 0.30, 0.15; power use (kJ/kWh): 10.29, 7.91; annual availability (%): 70, 50; fuel price (USD/GJ): 1.00, 4.30; power price (USD/kWh): 4.28, 5.52. The investment cost for coal-fired plants covers new construction including flue gas purification. The integrated gasification combined cycle (IGCC) seems to be the future of coal-based powergeneration. The future problems to be addressed include ways to reduce air pollution, improving the efficiency of the gas-steam cycle, and improving the combustion process particularly with a view to reducing substantially its environmental impact. (P.A.). 4 figs., 4 tabs., 9 refs

Maximumpower point trackers (MPPTs) play an important role in photovoltaic (PV) power systems because they maximize the power output from a PV system for a given set of conditions, and therefore maximize the array efficiency. This paper presents a novel MPPT method based on fuzzy cognitive networks (FCN). The new method gives a good maximumpower operation of any PV array under different conditions such as changing insolation and temperature. The numerical results show the effectiveness of the proposed algorithm. (author)

Full Text Available This paper proposes a novel optimal current given (OCG maximumpower point tracking (MPPT control strategy based on the theory of power feedback and hill climb searching (HCS for a permanent magnet direct drive wind energy conversion system (WECS. The presented strategy not only has the advantages of not needing the wind speed and wind turbine characteristics of the traditional HCS method, but it also improves the stability and accuracy of MPPT by estimating the exact loss torque. The OCG MPPT control strategy is first carried out by simulation, then an experimental platform based on the dSPACE1103 controller is built and a 5.5 kW permanent magnet synchronous generator (PMSG is tested. Furthermore, the proposed method is compared experimentally with the traditional optimum tip speed ratio (TSR MPPT control. The experiments verify the effectiveness of the proposed OCG MPPT strategy and demonstrate its better performance than the traditional TSR MPPT control.

Highlights: • An improved maximumpower point tracking method for PV system was proposed. • Theoretical derivation procedure of the proposed method was provided. • Simulation models of MPPT trackers were established based on MATLAB/Simulink. • Experiments were conducted to verify the effectiveness of the proposed MPPT method. - Abstract: Maximumpower point tracking (MPPT) algorithms play an important role in the optimization of the power and efficiency of a photovoltaic (PV) generation system. According to the contradiction of the classical Perturb and Observe (P and Oa) method between the corresponding speed and the tracking accuracy on steady-state, an improved P and O (P and Ob) method has been put forward in this paper by using the Atken interpolation algorithm. To validate the correctness and performance of the proposed method, simulation and experimental study have been implemented. Simulation models of classical P and Oa method and improved P and Ob method have been established by MATLAB/Simulink to analyze each technique under varying solar irradiation and temperature. The experimental results show that the tracking efficiency of P and Ob method is an average of 93% compared to 72% for P and Oa method, this conclusion basically agree with the simulation study. Finally, we proposed the applicable conditions and scope of these MPPT methods in the practical application

This paper presents comprehensive performance analyses and comparisons for air-standard irreversible thermodynamic cycle engines (TCE) based on the power output, power density, thermal efficiency, maximum dimensionless power output (MP), maximum dimensionless power density (MPD) and maximum thermal efficiency (MEF) criteria. Internal irreversibility of the cycles occurred during the irreversible-adiabatic processes is considered by using isentropic efficiencies of compression and expansion processes. The performances of the cycles are obtained by using engine design parameters such as isentropic temperature ratio of the compression process, pressure ratio, stroke ratio, cut-off ratio, Miller cycle ratio, exhaust temperature ratio, cycle temperature ratio and cycle pressure ratio. The effects of engine design parameters on the maximum and optimal performances are investigated. - Highlights: • Performance analyses are conducted for irreversible thermodynamic cycle engines. • Comprehensive computations are performed. • Maximum and optimum performances of the engines are shown. • The effects of design parameters on performance and power density are examined. • The results obtained may be guidelines to the engine designers

A structural integrity of steam generator tubes of nuclear power plants is one of crucial parameters for safe operation of nuclear power plants. Thus, many studies have been made to provide engineering methods to assess integrity of defective tubes of commercial nuclear power plants considering its operating environments and defect characteristics. As described above, the geometric and operating conditions of steam generator tubes in integral reactor are significantly different from those of commercial reactor. Therefore, the structural integrity assessment of defective tubes of integral reactor taking into account its own operating conditions and geometric characteristics, i. e., external pressure and helically coiled shape, should be made to demonstrate compliance with the current design criteria. Also, ovality is very specific characteristics of the helically coiled tube because it is occurred during the coiling processes. The wear, occurring from FIV (Flow Induced Vibration) and so on, is main degradation of steam generator tube. In the present study, maximum external pressure of helically coiled steam generator tube with wear is predicted based on the detailed 3-dimensional finite element analysis. As for shape of wear defect, the rectangular shape is considered. In particular, the effect of ovality on the maximum external pressure of helically coiled tubes with rectangular shaped wear is investigated. In the present work, the maximum external pressure of helically coiled steam generator tube with rectangular shaped wear is investigated via detailed 3-D FE analyses. In order to cover a practical range of geometries for defective tube, the variables affecting the maximum external pressure were systematically varied. In particular, the effect of tube ovality on the maximum external pressure is evaluated. It is expected that the present results can be used as a technical backgrounds for establishing a practical structural integrity assessment guideline of

The historically high cost of crude oil price is stimulating research into solar (green) energy as an alternative energy source. In general, applications with large solar energy output require a maximumpower point tracking (MPPT) algorithm to optimize the powergenerated by the photovoltaic effect. This work aims to provide a stand-alone solution for solar energy applications by integrating a DC/DC buck converter to a newly developed quadratic MPPT algorithm along with its appropriate software and hardware. The quadratic MPPT method utilizes three previously used duty cycles with their corresponding power outputs. It approaches the maximum value by using a second order polynomial formula, which converges faster than the existing MPPT algorithm. The hardware implementation takes advantage of the real-time controller system from National Instruments, USA. Experimental results have shown that the proposed solar mechatronics system can correctly and effectively track the maximumpower point without any difficulties. (author)

Full Text Available Scientists are looking for ways to improve the efficiency of solar cells all the time. The efficiency of solar cells which are available to the general public is up to 20%. Part of the solar energy is unused and a capacity of solar power plant is significantly reduced – if slow controller or controller which cannot stay at maximumpower point of solar modules is used. Various algorithms of maximumpower point tracking were created, but mostly algorithms are slow or make mistakes. In the literature more and more oftenartificial neural networks (ANN in maximumpower point tracking process are mentioned, in order to improve performance of the controller. Self-learner artificial neural network and IncCond algorithm were used for maximumpower point tracking in created solar power plant model. The algorithm for control was created. Solar power plant model is implemented in Matlab/Simulink environment.

Wind energy technology has experienced important improvements this last decade. The transition from fixed speed to variable speed wind turbines has been a significant element of these improvements. It has allowed adapting the turbine rotational speed to the wind speed variations with the aim of optimizing the aerodynamic efficiency. A classic controller that has slow dynamics relative to the mechanical dynamics of the drive train is implemented in commercial wind turbines. The objective of the work related in this paper has been to evaluate the implementation, on a test bench, of a controller whose dynamics can be adjusted to be faster and to compare in particular its aerodynamic efficiency with the conventional controller. In theory, the higher dynamics of the non-classic controller has to lead to a better efficiency. A 180 kW wind turbine whose simulation model has been validated with field data is emulated on an 18 kW test bench. The emulator has also been validated. Test bench trials are a very useful step between numerical simulation and trials on the real system because they allow analyzing some phenomena that may not appear in simulations without endangering the real system. The trials on the test bench show that the non-conventional controller leads to a higher aerodynamic efficiency and that this is offset by higher mechanical torque and electric power fluctuations. Nevertheless, the amplitudes of these fluctuations are relatively low compared to their rated values

The first direct measurements of antiproton stopping powers around the stopping powermaximum are presented. The LEAR antiproton-beam of 5.9 MeV is degraded to 50-700 keV, and the energy-loss is found by measuring the antiproton velocity before and after the target. The antiproton stopping powers of Si and Au are found to be reduced by 30 and 40% near the electronic stopping powermaximum as compared to the equivalent proton stopping power. The Barkas effect, that is the stopping power difference between protons and antiprotons, is extracted and compared to theoretical estimates. (orig.)

The maximumpower point tracking control is the key link to improve the energy conversion efficiency of wave energy converters (WEC). This paper presents a novel variable step size Perturb and Observe maximumpower point tracking algorithm with a power classification standard for control of a buoy-rope-drum WEC. The algorithm and simulation model of the buoy-rope-drum WEC are presented in details, as well as simulation experiment results. The results show that the algorithm tracks the maximumpower point of the WEC fast and accurately.

According to estimation guidance, power rates in general are the proper cost plus the specific compensation and adjustment addition. However, the current system of power rates is of power-source development promotion type involving its tax. The structure of power rate determination must be restudied now especially in connection of nuclear powergeneration. The cost of nuclear powergeneration as viewed from power rate is discussed as follows: the fear of military application of power plants, rising plant construction costs, the loophole in fuel cost calculation, unreasonable unit power cost, depreciation and repair cost, business compensation, undue business compensation in nuclear power, the costs of nuclear waste management, doubt concerning nuclear power cost, personnel, pumping-up and power transmission costs in nuclear power, energy balance analysis, nuclear power viewed in entropy, the suppression of power consumption. (J.P.N.)

This paper presents the design of an L1 adaptive controller for maximumpower point tracking (MPPT) of a small variable speed Wind Energy Conversion System (WECS). The proposed controller generates the optimal torque command for the vector controlled generator side converter (GSC) based on the wi......) is used to carry out case studies using Matlab/Simulink. The case study results show that the designed L1 adaptive controller has good tracking performance even with unmodeled dynamics and in the presence of parameter uncertainties and unknown disturbances.......This paper presents the design of an L1 adaptive controller for maximumpower point tracking (MPPT) of a small variable speed Wind Energy Conversion System (WECS). The proposed controller generates the optimal torque command for the vector controlled generator side converter (GSC) based on the wind...

This paper proposes two methods of maximumpower point tracking using a fuzzy logic and a neural network controllers for photovoltaic systems. The two maximumpower point tracking controllers receive solar radiation and photovoltaic cell temperature as inputs, and estimated the optimum duty cycle corresponding to maximumpower as output. The approach is validated on a 100 Wp PVP (two parallels SM50-H panel) connected to a 24 V dc load. The new method gives a good maximumpower operation of any photovoltaic array under different conditions such as changing solar radiation and PV cell temperature. From the simulation and experimental results, the fuzzy logic controller can deliver more power than the neural network controller and can give more power than other different methods in literature. (author)

The behavior of stimulated Brillouin scattering (SBS) and Rayleigh backscattering phenomena, which limit the forward transmission power in modern, ultra-long haul optical communication systems such as dense wavelength division multiplexing systems is analyzed via simulation and experimental investigation of threshold and maximumpower. Evolution of SBS, Rayleigh scattering and forward powers are experimentally investigated with a 25 km segment of single mode fiber. Also, a simple algorithm to predict the generation of SBS is proposed where two criteria of power thresholds was used for comparison with experimental data. (paper)

Distributed reactive power supply is necessary in distribution networks for an optimized network operation. This paper presents first the reactive power supply capabilities of generators connected to the distribution network (distributed generators). In a second step an approach is proposed of determining the energy losses resulting from reactive power supply by distributed generators. The costs for compensating these losses represent the operational costs of reactive power supply. These cost...

A maximumpower point tracking scheme for a 1kw stand-alone solar energy based power supply. ... Nigerian Journal of Technology ... A method for efficiently maximizing the output power of a solar panel supplying a load or battery bus under ...

Photovoltaic powergeneration has become the main research direction of new energy powergeneration. But high investment and low efficiency of photovoltaic industry arouse concern in some extent. So maximumpower point tracking of photovoltaic powergeneration has been a popular study point. Due to slow response, oscillation at maximumpower point and low precision, the algorithm based on genetic algorithm combined with BP neural network are designed detailedly in this paper. And the modeling and simulation are completed by use of MATLAB/SIMULINK. The results show that the algorithm is effective and the maximumpower point can be tracked accurately and quickly.

Full Text Available A maximumpower tracking algorithm exploiting operating point information gained on individual solar panels is presented. The proposed algorithm recognizes the presence of multiple local maxima in the power voltage curve of a shaded solar field and evaluates the coordinated of the absolute maximum. The effectiveness of the proposed approach is evidenced by means of circuit level simulation and experimental results. Experiments evidenced that, in comparison with a standard perturb and observe algorithm, we achieve faster convergence in normal operating conditions (when the solar field is uniformly illuminated and we accurately locate the absolute maximumpower point in partial shading conditions, thus avoiding the convergence on local maxima.

price thresholds are significantly higher when the monopolist at the peakload level owns both types of generators. Furthermore, when producing electricity with the peakload generator, the monopolist can avoid facing prices below marginal cost by owning a certain share of the wind generators.......Electricity production from wind generators holds significant importance in European Union’s 20% renewable energy target by 2020. In this paper, I show that ownership of wind generators affects market outcomes by using both a Cournot oligopoly model and a real options model. In the Cournot...... oligopoly model, ownership of the wind generators by owners of fossil-fueled (peakload) generators decreases total peakload production and increases the market price. These effects increase with total wind generation and aggregate wind generator ownership. In the real options model, start up and shut down...

Full Text Available Generation of electricity using diesel is costly for small remote isolated communities. At remote location electricity generation from renewable energy such as wind can help reduce the overall operating costs by reducing the fuel costs. However, the penetration of wind power into small diesel-based grids is limited because of its effect on power quality and reliability. This paper focuses on the combination of Wind Turbine and Diesel Generator systems for sustained powergeneration, to improve the power quality of wind generation system. The performances of the optimal control structure are assessed and discussed by means of a set of simulations.

Global demand for electricity is increasing while production of energy from fossil fuels is declining and therefore the obvious choice of the clean energy source that is abundant and could provide security for development future is energy from the sun. In this paper, the characteristic of the supply voltage of the photovoltaic generator is nonlinear and exhibits multiple peaks, including many local peaks and a global peak in non-uniform irradiance. To keep global peak, MPPT is the important component of photovoltaic systems. Although many review articles discussed conventional techniques such as P & O, incremental conductance, the correlation ripple control and very few attempts have been made with intelligent MPPT techniques. This document also discusses different algorithms based on fuzzy logic, Ant Colony Optimization, Genetic Algorithm, artificial neural networks, Particle Swarm Optimization Algorithm Firefly, Extremum seeking control method and hybrid methods applied to the monitoring of maximum value of power at point in systems of photovoltaic under changing conditions of irradiance.

Full Text Available The generation of electricity from photovoltaic (PV arrays has been increasingly considered as a prominent alternative to fossil fuels. However, the conversion efficiency is typically low and the initial cost is still appreciable. A required feature of a PV system is the ability to track the maximumpower point (MPP of the PV array. Besides, MPP tracking (MPPT is desirable in both grid-connected and stand-alone photovoltaic systems because the solar irradiance and temperature change throughout the day, as well as along seasons and geographical conditions, also leading to the modification of the I×V (current versus voltage and P×V (power versus voltage curves of the PV module. MPPT is also justified by the relatively high cost of the energy generated by PV systems if compared with other sources. Since there are various MPPT approaches available in the literature, this work presents a comparative study among four popular techniques, which are the fixed duty cycle method, constant voltage (CV, perturb and observe (P&O, and incremental conductance (IC. It considers different operational climatic conditions (i.e., irradiance and temperature, since the MPP is nonlinear with the environment status. PSIM software is used to validate the assumptions, while relevant results are discussed in detail.

Full Text Available Power system control is a complex task, which is strongly related to the number and kind of generating units as well as to the applied technologies, such as conventional coal fired power plants or wind and photovoltaic farms. Fast development of wind generation that is considered as unstable generation sets new strong requirements concerning remote control and data hubs cooperating with SCADA systems. Considering specific nature of the wind powergeneration, the authors analyze the problem of optimal control for wind powergeneration in farms located over a selected remote-controlled part of the Operator grid under advantageous wind conditions. This article presents an original stepwise method for tracing power flows that makes possible to eliminate current (power overloading of power grid branches. Its core idea is to consider the discussed problem as an optimization task.

Photovoltaic (PV) solar arrays are particularly useful for electrical powergeneration in remote, off-grid areas in developing countries. However, PV arrays offer a small power to area ratio, resulting in the need for more PV arrays which increases the cost of the system. In order to improve the profitability of PV arrays, the power extraction from available PV array systems must be maximized. This paper presented an analysis, modeling and implementation of an efficient solar charge controller. It was shown that the maximumpower of a photovoltaic system depends largely on temperature and insolation. A perturb and observe algorithm was used for maximumpower point tracking (MPPT). MPPT maximizes the efficiency of a solar PV system. A solar charge controller determines the optimal values of output current and voltage of converters to maximize power output for battery charging. In order to improve performance and implement the perturb and observe algorithm, the authors designed a fuzzy rule-based system in which a solar charge controller worked with a PWM controlled DC-DC converter for battery charging. The system was implemented on a low-cost PIC microcontroller. Results were better than conventional techniques in power efficiency. Swift maximumpower point tracking was obtained. 13 refs., 1 tab., 11 figs.

Areva Bioenergies proposes ready-to-use biogas production and valorization units that use industrial effluents (liquid effluents, spent water, solid wastes). Biogas valorization is performed through cogeneration plants with an output power of 500 kW to 10 MW. This brochure presents Areva's global offer in methanation projects (support, engineering, optimization). Areva Bioenergies counts 20 dual-purpose power plants in operation or under construction in the world which represent an installed power of 220 MW

A new method is proposed to generate text material for assessing maximum reading speed of adult readers. The described procedure allows one to generate a vast number of equivalent short sentences. These sentences can be displayed for different durations in order to determine the reader's maximum speed using a psychophysical threshold algorithm. Each sentence is built so that it is either true or false according to common knowledge. The actual reading is verified by asking the reader to determine the truth value of each sentence. We based our design on the generator described by Crossland et al. and upgraded it. The new generator handles concepts distributed in an ontology, which allows an easy determination of the sentences' truth value and control of lexical and psycholinguistic parameters. In this way many equivalent sentence can be generated and displayed to perform the measurement. Maximum reading speed scores obtained with pseudo-randomly chosen sentences from the generator were strongly correlated with maximum reading speed scores obtained with traditional MNREAD sentences (r = .836). Furthermore, the large number of sentences that can be generated makes it possible to perform repeated measurements, since the possibility of a reader learning individual sentences is eliminated. Researchers interested in within-reader performance variability could use the proposed method for this purpose.

of the converter interfacing a wind powergeneration unit is also given. The power electronic interface performs the optimal operation in the wind turbine system to extract the maximum wind power, while it also plays a key role in a hybrid compensation system that consists of the active power electronic converter......This paper presents a power electronic converter which is used as an interface for a distributed generation unit/energy storage device, and also functioned as an active power compensator in a hybrid compensation system. The operation and control of the converter have been described. An example...... and passive filters connected to each distorting load or distributed generation (DG) unit. The passive filters are distributely located to remove major harmonics and provide reactive power compensation. The active power electronic filter corrects the system unbalance, removes the remaining harmonic components...

Full Text Available Photovoltaic traffic light system is a significant application of renewable energy source. The development of the system is an alternative effort of local authority to reduce expenditure for paying fees to power supplier which the power comes from conventional energy source. Since photovoltaic (PV modules still have relatively low conversion efficiency, an alternative control of maximumpower point tracking (MPPT method is applied to the traffic light system. MPPT is intended to catch up the maximumpower at daytime in order to charge the battery at the maximum rate in which the power from the battery is intended to be used at night time or cloudy day. MPPT is actually a DC-DC converter that can step up or down voltage in order to achieve the maximumpower using Pulse Width Modulation (PWM control. From experiment, we obtained the voltage of operation using MPPT is at 16.454 V, this value has error of 2.6%, if we compared with maximumpower point voltage of PV module that is 16.9 V. Based on this result it can be said that this MPPT control works successfully to deliver the power from PV module to battery maximally.

A thermoelectric powergenerator is disclosed for use to generate electrical power from heat, typically waste heat. An intermediate heat transfer loop forms a part of the system to permit added control and adjustability in the system. This allows the thermoelectric powergenerator to more effectively and efficiently generatepower in the face of dynamically varying temperatures and heat flux conditions, such as where the heat source is the exhaust of an automobile, or any other heat source with dynamic temperature and heat flux conditions.

Information on wind power is presented concerning the history of windmills; estimation of the energy obtainable from the wind; wind characteristics and distribution; wind power sites; wind surveys; wind flow over hills; measurement of wind velocity; wind structure and its determination; wind data and energy estimation; testing of wind driven ac generators; wind-driven machines; propeller type windmills; plants for isolated premises and small communities; economy of wind powergeneration; construction costs for large wind-driven generators; relationship of wind power to other power sources; research and development; and international cooperation.

Characteristics are presented for two different types of explosive driven flux compression generators and a megavolt pulse transformer. Status reports are given for rail gun and plasma focus programs for which the generators serve as power sources

Purpose: To enable to perform stable and dynamic conditioning operation for nuclear fuels in BWR type reactors. Constitution: The conditioning operation for the nuclear fuels is performed by varying the reactor core thermal power in a predetermined pattern by changing the predetermined power changing pattern of generatorpower, the rising rate of the reactor core thermal power and the upper limit for the rising power of the reactor core thermal power are calculated and the power pattern for the generator is corrected by a power conditioning device such that the upper limit for the thermal power rising rate and the upper limit for the thermal power rising rate are at the predetermined levels. Thus, when the relation between the reactor core thermal power and the generator electrical power is fluctuated, the fluctuation is detected based on the variation in the thermal power rising rate and the limit value for the thermal power rising rate, and the correction is made to the generatorpower changing pattern so that these values take the predetermined values to thereby perform the stable conditioning operation for the nuclear fuels. (Moriyama, K.)

The article deals with an analysis of directly driven, low-speed wind generators. The generators studied were a permanent-magnet synchronous machine and an asynchronous machine. The machines were compared with a typical generator of a wind power plant. The electromagnetic optimization of the machines was done by the finite element method. The rated power of the generators was 500 kW and the rotational speed was 40 rpm. (author)

The article deals with an analysis of directly driven, low-speed wind generators. The generators studied were a permanent-magnet synchronous machine and an asynchronous machine. The machines were compared with a typical generator of a wind power plant. The electromagnetic optimization of the machines was done by the finite element method. The rated power of the generators was 500 kW and the rotational speed was 40 rpm. (author)

The counter-rotating proton beams in the Large Hadron Collider (LHC) will be captured and then accelerated to their final energies of 2 x 7 TeV by two identical 400 MHz RF systems. The RF power source required for each beam comprises eight 300 kW klystrons. The output power of each klystron is fed via a circulator and a waveguide line to the input coupler of a single-cell super-conducting (SC) cavity. Four klystrons are powered by a 100 kV, 40A AC/DC power converter, previously used for the operation of the LEP klystrons. A five-gap thyratron crowbar protects the four klystrons in each of these units. The technical specification and measured performance of the various high-power elements are discussed. These include the 400MHz/300kW klystrons with emphasis on their group delay and the three-port circulators, which have to cope with peak reflected power levels up to twice the simultaneously applied incident power of 300 kW. In addition, a novel ferrite loaded waveguide absorber, used as termination for port No...

The paper presents discussions on the following topics: fuel supply for nuclear power; expansion of the sphere of nuclear power applications, such as district heating; comparative estimates of power reactor efficiencies; safety philosophy of advanced nuclear plants, including passive protection and inherent safety concepts; nuclear power unit of enhanced safety for the new generation of nuclear power plants. The emphasis is that designers of new generation reactors face a complicated but technically solvable task of developing highly safe, efficient, and economical nuclear power sources having a wide sphere of application

Full Text Available Maximumpower point tracking is a mature control issue for wind, solar and other systems. On the other hand, being a relatively new technology, detailed discussion on power tracking of hydrokinetic energy conversion systems are generally not available. Prior to developing sophisticated control schemes for use in hydrokinetic systems, existing know-how in wind or solar technologies can be explored. In this study, a comparative evaluation of three generic classes of maximumpower point scheme is carried out. These schemes are (a tip speed ratio control, (b power signal feedback control, and (c hill climbing search control. In addition, a novel concept for maximumpower point tracking: namely, extremum seeking control is introduced. Detailed and validated system models are used in a simulation environment. Potential advantages and drawbacks of each of these schemes are summarised.

The performance of photovoltaic systems is often reduced by the presence of partial shadows. The system efficiency and availability can be improved by a maximumpower point tracking algorithm that is able to detect partial shadow conditions and to optimize the power output. This work proposes...... an intelligent maximumpower point tracking method that monitors the maximumpower point voltage and triggers a current-voltage sweep only when a partial shadow is detected, therefore minimizing power loss due to repeated current-voltage sweeps. The proposed system is validated on an advanced, flexible...... photovoltaic inverter system test platform that is able to reproduce realistic partial shadow conditions, both in simulation and on hardware test system....

One field in which electronic materials have an important role is energy generation, especially within the scope of photovoltaic energy. This paper deals with one of the most relevant enabling technologies within that scope, i.e, the algorithms for maximumpower point tracking implemented in the direct current to direct current converters and its modeling through artificial neural networks (ANNs). More specifically, as a proof of concept, we have addressed the problem of modeling a fuzzy logic controller that has shown its performance in previous works, and more specifically the dimensionless duty cycle signal that controls a quadratic boost converter. We achieved a very accurate model since the obtained medium squared error is 3.47 × 10-6, the maximum error is 16.32 × 10-3 and the regression coefficient R is 0.99992, all for the test dataset. This neural implementation has obvious advantages such as a higher fault tolerance and a simpler implementation, dispensing with all the complex elements needed to run a fuzzy controller (fuzzifier, defuzzifier, inference engine and knowledge base) because, ultimately, ANNs are sums and products.

There are considerably many investigations and researches on the attitude of general public to nuclear powergeneration, but those which analyzed the contents of attitude or the research which got into the problem of what method is desirable to obtain the understanding of nuclear powergeneration for powergeneration side is rarely found. Therefore, the research on where is its cause was begun. As the result, since the attitude to nuclear powergeneration is related to the attitudes to many things that surround nuclear powergeneration in addition to that directly to nuclear powergeneration, it is necessary to elucidate the problem synthetically. The social investigation was carried out for the public of from 18 to 79 years old who live in the supply area of Kansai Electric Power Co., Inc. The data were obtained from those selected by probabilistic sampling, 1000 in urban area (rate of recovery 76%) and 440 in country area (rate of recovery 77%). The way of thinking on making questionnaire is shown. The investigation and the analysis of the obtained data were carried out. What do you recollect as a dangerous matter, the attitude to nuclear powergeneration, the structure of the conscience to nuclear powergeneration and its significance, the type classification of people and its features are reported and discussed. (K.I.)

ABSTRACT: The power developed in a solar energy system depends fundamentally upon the ... for powergeneration. ... determined because they are functions of the solar angles that ..... able to withstand the weight and the blowing wind.

object of the article is thus to cover some of the milestones of thermodynamics, and show through the illustrative case of thermoelectric generators, our model heat engine, that the shift from Carnot's efficiency to efficienc ies at maximumpower explains itself naturally as one considers continuity and boundary conditions carefully; indeed, as an adaptation of Friedrich Nietzche's quote, we may say that the thermodynamic demon is in the details. This article is supplemented with comments by J.M.R. Parrondo and a final reply by the authors.

Owing to increased emphasis on renewable resources, the development of suitable isolated powergenerators driven by energy sources, the development of suitable isolated powergenerators driven by energy sources such as photovoltaic, wind, small hydroelectric, biogas and etc. has recently assumed greater significance. A single phase capacitor self excited induction generator has emerged as a suitable candidate of isolated power sources. This paper presents performance analysis of a single phase self-excited induction generator driven by photovoltaic (P V) system for low power isolated stand-alone applications. A single phase induction machine can work as a self-excited induction generator when its rotor is driven at suitable speed by an photovoltaic powered do motor. Its excitation is provided by connecting a single phase capacitor bank at a stator terminals. Either to augment grid power or to get uninterrupted power during grid failure stand-alone low capacity ac generators are used. These are driven by photovoltaic, wind power or I C engines using kerosene, diesel, petrol or biogas as fuel. Self-excitation with capacitors at the stator terminals of the stator terminals of the induction machines is well demonstrated experimentally on a P V powered dc motor-induction machine set. The parameters and the excitation requirements of the induction machine run in self-excited induction generator mode are determined. The effects of variations in prime mover speed,terminal capacitance and load power factor on the machine terminal voltage are studied

A generator permitting to shape on the load pulsed with the repetition frequency of 10 3 -10 6 Hz and more is described. The amplitude of shaped voltage pulses is up to 150 kV at pulse duration equal to 50 ns. The generator comprises connected in-series with the load two shaping and two transmission lines realized on the base of the KVI-300 low-ohmic cable. The shaping lines are supplied from two independently connected pulse voltage generators for obtaining time interval between pulses > 10 -6 s; they may be also supplied from one generator for obtaining time interval -6 s. At the expense of reducing losses in the discharge circuit the amplitude of the second pulse grows with increase of time interval between pulses up to 300 ns, further on the curve flat-topping exists. The described generator is used in high-current accelerators, in which the primary negative pulse results in generation of explosive-emission plasma, and the second positive pulse provides ion beam shaping including ions of heavy metal used for production of a potential electrode. The generator multipulse mode is used for successive ion acceleration in the transport system

Photovoltaic power plants (PVPPs) typically operate by tracking the maximumpower point in order to maximize conversion efficiency. However, with the continuous increase of installed grid-connected PVPPs, power system operators have been experiencing new challenges, like overloading, overvoltages...... on a hysteresis band controller in order to obtain fast dynamic response under transients and low power oscillation during steady-state operation. The performance of the proposed algorithm for both single- and two-stage PVPPs is examined on a 50-kVA simulation setup of these topologies. Moreover, experimental...... and operation during grid voltage disturbances. Consequently, constant powergeneration (CPG) is imposed by grid codes. An algorithm for the calculation of the photovoltaic panel voltage reference, which generates a constant power from the PVPP, is introduced in this paper. The key novelty of the proposed...

Characterization of thermoelectric generators (TEG) is widely discussed and equipment has been built that can perform such analysis. One method is often used to perform such characterization: constant temperature with variable thermal power input. Maximumpower point tracking (MPPT) methods for TEG systems are mostly tested under steady-state conditions for different constant input temperatures. However, for most TEG applications, the input temperature gradient changes, exposing the MPPT to variable tracking conditions. An example is the exhaust pipe on hybrid vehicles, for which, because of the intermittent operation of the internal combustion engine, the TEG and its MPPT controller are exposed to a cyclic temperature profile. Furthermore, there are no guidelines on how fast the MPPT must be under such dynamic conditions. In the work discussed in this paper, temperature gradients for TEG integrated in several applications were evaluated; the results showed temperature variation up to 5°C/s for TEG systems. Electrical characterization of a calcium-manganese oxide TEG was performed at steady-state for different input temperatures and a maximum temperature of 401°C. By using electrical data from characterization of the oxide module, a solar array simulator was emulated to perform as a TEG. A trapezoidal temperature profile with different gradients was used on the TEG simulator to evaluate the dynamic MPPT efficiency. It is known that the perturb and observe (P&O) algorithm may have difficulty accurately tracking under rapidly changing conditions. To solve this problem, a compromise must be found between the magnitude of the increment and the sampling frequency of the control algorithm. The standard P&O performance was evaluated experimentally by using different temperature gradients for different MPPT sampling frequencies, and efficiency values are provided for all cases. The results showed that a tracking speed of 2.5 Hz can be successfully implemented on a TEG

In future large capacity nuclear power plant, capacity of a generator to be applied will be 1800 MVA of the largest class in the world. In response to this, the Mitsubishi Electric Co., Ltd. began to carry out element technology verification of a four-pole large capacity turbine generator mainly using upgrading technique of large capacity, since 1994 fiscal year. And, aiming at reliability verification of the 1800 MVA class generator, a model generator with same cross-section as that of an actual one was manufactured, to carry out some verifications on its electrified tests, and so on. Every performance evaluation result of tests on the model generator were good, and high reliability to design and manufacturing technique of the 1800 MVA class generator could be verified. In future, on the base of these technologies, further upgrading of reliability on the large capacity turbine generator for nuclear powergeneration is intended to be carried out. (G.K.)

The 'Technical Committee on Advanced Energy Utilization MHD PowerGeneration' was started to establish advanced energy utilization technologies in Japan, and has been working for three years from June 2004 to May 2007. This committee investigated closed cycle MHD, open cycle MHD, and liquid metal MHD powergeneration as high-efficiency powergeneration systems on the earth. Then, aero-space application and deep space exploration technologies were investigated as applications of MHD technology. The spin-off from research and development on MHD powergeneration such as acceleration and deceleration of supersonic flows was expected to solve unstart phenomena in scramjet engine and also to solve abnormal heating of aircrafts by shock wave. In addition, this committee investigated researches on fuel cells, on secondary batteries, on connection of wind power system to power grid, and on direct energy conversion system from nuclear fusion reactor for future. The present technical report described results of investigations by the committee. (author)

This paper proposes an artificial neural network maximumpower point tracker (MPPT) for solar electric vehicles. The MPPT is based on a highly efficient boost converter with insulated gate bipolar transistor (IGBT) power switch. The reference voltage for MPPT is obtained by artificial neural network (ANN) with gradient descent momentum algorithm. The tracking algorithm changes the duty-cycle of the converter so that the PV-module voltage equals the voltage corresponding to the MPPT at any given insolation, temperature, and load conditions. For fast response, the system is implemented using digital signal processor (DSP). The overall system stability is improved by including a proportional-integral-derivative (PID) controller, which is also used to match the reference and battery voltage levels. The controller, based on the information supplied by the ANN, generates the boost converter duty-cycle. The energy obtained is used to charge the lithium ion battery stack for the solar vehicle. The experimental and simulation results show that the proposed scheme is highly efficient.

The HANARO fuel, U{sub 3}Si-Al, has been developed by AECL and tested in NRU reactor. Due to the lack of the data performed under the high power, the repetitive conduct of the irradiation test was required under the power greater than 108kW/m, which is the estimated maximum linear power in the design stage. Accordingly, the instrumented test bundle with SPND(Self Powered Neutron Detector) was fabricated and its irradiation test was performed in IR2 of HANARO. The measured thermal neutron flux with SPND is compared with calculation results by HANAFMS(HANARO Fuel Management System). The difference in the measured and calculated thermal flux values are below {+-}11% and the accuracy of the linear power predicted by HANAFMS is consequently accompanied. Therefore, it is believed that the maximum linear power above 120kW/m is achieved during the irradiation test of the test bundle.

Stochastic generation, i.e., electrical power production by an uncontrolled primary energy source, is expected to play an important role in future power systems. A new power system structure is created due to the large-scale implementation of this small-scale, distributed, non-dispatchable

Microwave Power Engineering, Volume 1: Generation, Transmission, Rectification considers the components, systems, and applications and the prevailing limitations of the microwave power technology. This book contains four chapters and begins with an introduction to the basic concept and developments of microwave power technology. The second chapter deals with the development of the main classes of high-power microwave and optical frequency powergenerators, such as magnetrons, crossed-field amplifiers, klystrons, beam plasma amplifiers, crossed-field noise sources, triodes, lasers. The third

Inventive concentrated solar power systems using solar receivers, and related devices and methods, are generally described. Low pressure solar receivers are provided that function to convert solar radiation energy to thermal energy of a working fluid, e.g., a working fluid of a powergeneration or thermal storage system. In some embodiments, low pressure solar receivers are provided herein that are useful in conjunction with gas turbine based powergeneration systems.

The purpose of this study is to clarify the role of nuclear powergeneration under the circumstances of growing concerns about environmental impact and to help decision making in electricity sector. In this study, efforts are made to estimate electricity powergeneration cost of major power options by incorporating additional cost to reduce environmental impact and to suggest an optimal plant mix in this case. (Author)

Full Text Available The organization of drainage basins shows some reproducible phenomena, as exemplified by self-similar fractal river network structures and typical scaling laws, and these have been related to energetic optimization principles, such as minimization of stream power, minimum energy expenditure or maximum "access". Here we describe the organization and dynamics of drainage systems using thermodynamics, focusing on the generation, dissipation and transfer of free energy associated with river flow and sediment transport. We argue that the organization of drainage basins reflects the fundamental tendency of natural systems to deplete driving gradients as fast as possible through the maximization of free energy generation, thereby accelerating the dynamics of the system. This effectively results in the maximization of sediment export to deplete topographic gradients as fast as possible and potentially involves large-scale feedbacks to continental uplift. We illustrate this thermodynamic description with a set of three highly simplified models related to water and sediment flow and describe the mechanisms and feedbacks involved in the evolution and dynamics of the associated structures. We close by discussing how this thermodynamic perspective is consistent with previous approaches and the implications that such a thermodynamic description has for the understanding and prediction of sub-grid scale organization of drainage systems and preferential flow structures in general.

Simulations have been performed to study the energy loss of carbon ions in a hot, laser-generated plasma in the velocity region of the stopping-powermaximum. In this parameter range, discrepancies of up to 30% exist between the various stopping theories and hardly any experimental data are available. The considered plasma, created by irradiating a thin carbon foil with two high-energy laser beams, is fully-ionized with a temperature of nearly 200 eV. To study the interaction at the maximum stopping power, Monte-Carlo calculations of the ion charge state in the plasma are carried out at a projectile energy of 0.5 MeV per nucleon. The predictions of various stopping-power theories are compared and experimental campaigns are planned for a first-time theory benchmarking in this low-velocity range. (paper)

Photovoltaic traffic light system is a significant application of renewable energy source. The development of the system is an alternative effort of local authority to reduce expenditure for paying fees to power supplier which the power comes from conventional energy source. Since photovoltaic (PV) modules still have relatively low conversion efficiency, an alternative control of maximumpower point tracking (MPPT) method is applied to the traffic light system. MPPT is intended to catch up th...

Approximately 15% of the worlds installed capacity in electric energy production is from generators developed and manufactured by GEC Alsthom. GEC Alsthom is now working on the application of generators for HTGR power conversion systems. The main generator characteristics induced by the different HTGR power conversion technology include helium immersion, high helium pressure, brushless excitation system, magnetic bearings, vertical lineshaft, high reliability and long periods between maintenance. (author)

Power is a well-established concept in the social sciences especially in the political sciences. Although it is widely used in scientific discourse, different definitions and perspectives prevail with regard to it. This article aims to explore the possibilities of taking the debate further towards a third generation definition of social power. Although first generation definitions (associated with Weber and Dahl) and second generation definitions (associated with inter alia Giddens and Morris...

The maximum efficiency for photovoltaic (PV) and thermoelectric generator (TEG) systems without concentration is investigated. Both a combined system where the TEG is mounted directly on the back of the PV and a tandem system where the incoming sunlight is split, and the short wavelength radiation...

This thesis presents the theoretical and simulation studies of the global maximumpower point tracking (MPPT) for photovoltaic systems under partial shading. The main goal is to track the maximumpower point of the photovoltaic module so that the maximum possible power can be extracted from the photovoltaic panels. When several panels are connected in series with some of them shaded partially either due to clouds or shadows from neighboring buildings, several local maxima appear in the power vs. voltage curve. A power increment based MPPT algorithm is effective in identifying the global maximum from the several local maxima. Several existing MPPT algorithms are explored and the state-of-the-art power increment method is simulated and tested for various partial shading conditions. The current-voltage and power-voltage characteristics of the PV model are studied under different partial shading conditions, along with five different cases demonstrating how the MPPT algorithm performs when shading switches from one state to another. Each case is supplemented with simulation results. The method of tracking the Global MPP is based on controlling the DC-DC converter connected to the output of the PV array. A complete system simulation including the PV array, the direct current to direct current (DC-DC) converter and the MPPT is presented and tested using MATLAB software. The simulation results show that the MPPT algorithm works very well with the buck converter, while the boost converter needs further changes and implementation.

The design and construction of nuclear power plants are executed to rigorous standards of safety and reliability. Similarly the human interface within the nuclear power plant must meet very high standards, and these must be demonstrated to be maintained and assured through time. The control room, as the operating nerve-centre of the plant, carries a large part of this responsibility. It is the work space dimension within which the operator-instrumentation interface must function as efficiently as possible. This paper provides an overview of how ergonomics has been used as a major tool in reshaping the man-machine interface within the control room in the interest of safety and reliability. Topics covered in the paper include workspace design, control panel layout, demarcation and labelling, switch and meter types, and annunciated and unannunciated alarms

The paper presents a novel two-stage particle swarm optimization (PSO) for the maximumpower point tracking (MPPT) control of a PV system consisting of cascaded PV-converter modules, under partial shading conditions (PSCs). In this scheme, the grouping method of the shuffled frog leaping algorithm (SFLA) is incorporated with the basic PSO algorithm, ensuring fast and accurate searching of the global extremum. An adaptive speed factor is also introduced to improve its convergence speed. A PWM algorithm enabling permuted switching of the PV sources is applied. The method enables this PV system to achieve the maximumpowergeneration for any number of PV and converter modules. Simulation studies of the proposed MPPT scheme are performed on a system having two chained PV buck-converter modules and a dc-ac H-bridge connected at its terminals for supplying an AC load. The results show that this type of PV system allows each module to achieve the maximumpowergeneration according its illumination level without affecting the others, and the proposed new control method gives significantly higher power output compared with the conventional P&O and PSO methods.

This work presents the development situation of biomass gasification powergeneration technology in China and analyzes the difficulty and challenge in the development process. For China, a large agricultural country with abundant biomass resources, the utilization of biomass gasification powergeneration technology is of special importance, because it can contribute to the electricity structure diversification under the present coal-dominant electricity structure, ameliorate the environmental impact, provide energy to electricity-scarce regions and solve the problems facing agriculture. Up to now, China has developed biomass gasification powergeneration plants of different types and scales, including simple gas engine-based powergeneration systems with capacity from several kW to 3 MW and integrated gasification combined cycle systems with capacity of more than 5 MW. In recent years, due to the rising cost of biomass material, transportation, manpower, etc., the final cost of biomass powergeneration has increased greatly, resulting in a serious challenge in the Chinese electricity market even under present preferential policy for biomass power price. However, biomass gasification powergeneration technology is generally in accord with the characteristics of biomass resources in China, has relatively good adaptability and viability, and so has good prospect in China in the future. - Highlights: ► Biomass gasification powergeneration of 2 kW–2 MW has wide utilization in China. ► 5.5 MW biomass IGCC demonstration plant has maximumpower efficiency of up to 30%. ► Biomass powergeneration is facing a serious challenge due to biomass cost increase.

In the frame of minimizing the operation-cost, operation mode using one line cooling system is being evaluated. Maximum reactor power shall be determined to assure that the existing safety criteria are not violated. The analysis was done by means of a core thermal hydraulic code, COOLOD-N. The code solves core thermal hydraulic equation at steady state conditions. By varying the reactor power as the input, thermal hydraulic parameters such as fuel cladding and fuel meat temperatures as well as safety margin against flow instability were calculated. Imposing the safety criteria to the results, maximum permissible power for this operation was obtained as much as 17.1 MW. Nevertheless, for operation the maximumpower is limited to 15MW

A totally implantable piezoelectric generator system able to harness power from electrically activated muscle could be used to augment the power systems of implanted medical devices, such as neural prostheses, by reducing the number of battery replacement surgeries or by allowing periods of untethered functionality. The features of our generator design are no moving parts and the use of a portion of the generatedpower for system operation and regulation. A software model of the system has been developed and simulations have been performed to predict the output power as the system parameters were varied within their constraints. Mechanical forces that mimic muscle forces have been experimentally applied to a piezoelectric generator to verify the accuracy of the simulations and to explore losses due to mechanical coupling. Depending on the selection of system parameters, software simulations predict that this generator concept can generate up to approximately 700 W of power, which is greater than the power necessary to drive the generator, conservatively estimated to be 50 W. These results suggest that this concept has the potential to be an implantable, self-replenishing power source and further investigation is underway.

Up to a recent past, most energy scenarios were foreseeing a fast growth of natural gas consumption thanks to an assumed strong penetration of gas-fueled power plants. The share of natural gas in the centralized powergeneration has been the subject of a meeting of the French gas association (AFG) which aimed at answering the following questions: today's position of gas powergeneration in Europe in the present day context of gas prices (level, volatility), the share of natural gas in the French power mix in the coming years, the strategies of development of gas power plants by historical operators and newcomers, the gas arbitration between its sale to end-users and its use for powergeneration, and the integration of the CO 2 risk. (J.S.)

A study was made of five potential approaches that can be utilized to detect the maximumpower point of a solar array while sustaining operations at or near maximumpower and without endangering stability or causing array voltage collapse. The approaches studied included: (1) dynamic impedance comparator, (2) reference array measurement, (3) onset of solar array voltage collapse detection, (4) parallel tracker, and (5) direct measurement. The study analyzed the feasibility and adaptability of these approaches to a future solar electric propulsion (SEP) mission, and, specifically, to a comet rendezvous mission. Such missions presented the most challenging requirements to a spacecraft power subsystem in terms of power management over large solar intensity ranges of 1.0 to 3.5 AU. The dynamic impedance approach was found to have the highest figure of merit, and the reference array approach followed closely behind. The results are applicable to terrestrial solar power systems as well as to other than SEP space missions.

Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximumpower point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximumpower point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximumpower point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximumpower point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

Maximumpower point tracking (MPPT) is a technique that charge controllers use for wind turbines and PV solar systems to maximize power output. PV solar systems exist in several different configurations. The most basic version sends power from collector panels directly to the DC-AC inverter and from there directly to the electrical grid. A second version, called a hybrid inverter, might split the power at the inverter, where a percentage of the power goes to the grid and the remainder goes to...

Full Text Available This paper is concerned with the modifications of maximum likelihood, moments and percentile estimators of the two parameter Power function distribution. Sampling behavior of the estimators is indicated by Monte Carlo simulation. For some combinations of parameter values, some of the modified estimators appear better than the traditional maximum likelihood, moments and percentile estimators with respect to bias, mean square error and total deviation.

Highlights: • Novel sensorless MPPT technique without drawbacks of other sensor/sensorless methods. • Tracking the actual MPP of WECSs, no tracking the MPP of their wind turbines. • Actually extracting the highest output power from WECSs. • Novel MPPT technique having the MPPT efficiency more than 98.5% for WECSs. • Novel MPPT technique having short convergence time for WECSs. - Abstract: In this study, a novel high accurate sensorless maximumpower point tracking (MPPT) method is proposed. The technique tracks the actual maximumpower point of a wind energy conversion system (WECS) at which maximum output power is extracted from the system, not the maximumpower point of its wind turbine at which maximum mechanical power is obtained from the turbine, so it actually extracts the highest output power from the system. The technique only uses input voltage and current of the converter used in the system, and neither needs any speed sensors (anemometer and tachometer) nor has the drawbacks of other sensor/sensorless based MPPT methods. The technique has been implemented as a MPPT controller by constructing a WECS. Theoretical results, the technique performance, and its advantages are validated by presenting real experimental results. The real static-dynamic response of the MPPT controller is experimentally obtained that verifies the proposed MPPT technique high accurately extracts the highest instant power from wind energy conversion systems with the MPPT efficiency of more than 98.5% and a short convergence time that is only 25 s for the constructed system having a total inertia and friction coefficient of 3.93 kg m 2 and 0.014 N m s, respectively.

A substantial growth of the installed photovoltaic systems capacity has occurred around the world during the last decade, thus enhancing the availability of electric energy in an environmentally friendly way. The maximumpower point tracking technique enables maximization of the energy production...... of photovoltaic sources during stochastically varying solar irradiation and ambient temperature conditions. Thus, the overall efficiency of the photovoltaic energy production system is increased. Numerous techniques have been presented during the last decade for implementing the maximumpower point tracking...... process in a photovoltaic system. This article provides an overview of the operating principles of these techniques, which are suited for either uniform or non-uniform solar irradiation conditions. The operational characteristics and implementation requirements of these maximumpower point tracking...

Full Text Available Solar photovoltaic (PV systems are a clean and naturally replenished energy source. PV panels have a unique point which represents the maximum available power and this point depend on the environmental conditions such as temperature and irradiance. A maximumpower point tracking (MPPT is therefore necessary for maximum efficiency. In this paper, a study of MPPT for PV water pumping system based on adaptive neuro-fuzzy inference system (ANFIS is discussed. A comparison between the performance of the system with and without MPPT is carried out under varying irradiation and temperature conditions. ANFIS based controller shows fast response with high efficiency at all irradiance and temperature levels making it a powerful technique for non-linear systems as PV modules. Keywords: MPPT, ANFIS, Boost converter, PMDC pump

In Japan, as the Rule on Electric Business was revised after an interval of 35 years in 1995, and a competitive bid on new electric source was adopted after 1996 fiscal year, investigation on further competition introduction to electric power market was begun by establishment of the Basic Group of the Electric Business Council in 1997. By a report proposed on January, 1999 by the Group, the Rule was revised again on March, 1999 to start a partial liberation or retail of the electric power from March, 2000. From a viewpoint of energy security and for solution of global environmental problem in Japan it has been decided to positively promote nuclear power in future. Therefore, it is necessary to investigate how the competition introduction affects to development of nuclear powergeneration and what is a market liberation model capable of harmonizing with the development on liberation of electric power market. Here was elucidated on effect of the introduction on previous and future nuclear powergeneration, after introducing new aspects of nuclear power problems and investigating characteristic points and investment risks specific to the nuclear powergeneration. And, by investigating some possibilities to development of nuclear powergeneration under liberation models of each market, an implication was shown on how to be future liberation on electric power market in Japan. (G.K.)

Recent advances in microfabrication technologies have enabled the development of entirely new classes of small-scale devices with applications in fields ranging from biomedicine, to wireless communication and computing, to reconnaissance, and to augmentation of human function. In many cases, however, what these devices can actually accomplish is limited by the low energy density of their energy storage and conversion systems. This breakthrough book brings together in one place the information necessary to develop the high energy density combustion-based power sources that will enable many of these devices to realize their full potential. Engineers and scientists working in energy-related fields will find: An overview of the fundamental physics and phenomena of microscale combustion; Presentations of the latest modeling and simulation techniques for gasphase and catalytic micro-reactors; The latest results from experiments in small-scale liquid film, microtube, and porous combustors, micro-thrusters, a...

Power electronics technology has become the enabling technology for the integration of distributed powergeneration systems (DPGS) such as offshore wind turbine power systems and commercial photovoltaic power plants. Depending on the applications, a vast array of DPGS-based power converter...... topologies has been developed and more are coming into the market in order to achieve an efficient and reliable power conversion from the renewables. In addition, stringent demands from both the distribution system operators and the consumers have been imposed on the renewable-based DPGS. This article...... presents an overview of the power converters for the DPGS, mainly based on wind turbine systems and photovoltaic systems, covering a wide range of applications. Moreover, the modulation schemes and interfacing power filters for the power converters are also exemplified. Finally, the general control...

Highlights: • Hybrid MPPT method was developed and utilized in a PV system of closed plant factory. • The tracking of the maximumpower output of PV system can be achieved in real time. • Hybrid MPPT method not only decreases energy loss but increases power utilization. • The feasibility of applying PV system to the closed plant factory has been examined. • The PV system significantly reduced CO 2 emissions and curtailed the fossil fuels. - Abstract: Photovoltaic (PV) generation systems have been shown to have a promising role for use in high electric-load buildings, such as the closed plant factory which is dependent upon artificial lighting. The powergenerated by the PV systems can be either directly supplied to the buildings or fed back into the electrical grid to reduce the high economic costs and environmental impact associated with the traditional energy sources such as nuclear power and fossil fuels. However, PV systems usually suffer from low energy-conversion efficiency, and it is therefore necessary to improve their performance by tackling the energy loss issues. The maximumpower point tracking (MPPT) control technique is essential to the PV-assisted generation systems in order to achieve the maximumpower output in real time. In this study, we integrate the previously proposed direct-prediction MPP method with a perturbation and observation (P and O) method to develop a new hybrid MPPT method. The proposed MPPT method is further utilized in the PV inverters in a PV system installed on the roof of a closed plant factory at National Taiwan University. The tested PV system is constructed as a two-stage grid-connected photovoltaic power conditioning (PVPC) system with a boost-buck full bridge design configuration. A control scheme based on the hybrid MPPT method is also developed and implemented in the PV inverters of the PVPC system to achieve tracking of the maximumpower output of the PV system in real time. Based on experimental results

Incentives provided by European governments have resulted in the rapid growth of the photovoltaic (PV) market. Many PV modules are now commercially available, and there are a number of power electronic systems for processing the electrical power produced by PV systems, especially for grid-connected applications. Filling a gap in the literature, Power Electronics and Control Techniques for Maximum Energy Harvesting in Photovoltaic Systems brings together research on control circuits, systems, and techniques dedicated to the maximization of the electrical power produced by a photovoltaic (PV) so

Maximum photovoltaic (PV) hosting capacity of low voltage (LV) power networks is mainly restricted by either thermal limits of network components or grid voltage quality resulted from high penetration of distributed PV systems. This maximum hosting capacity may be lower than the available solar...... potential of geographic area due to power network limitations even though all rooftops are fully occupied with PV modules. Therefore, it becomes more of an issue to know what exactly limits higher PV penetration level and which solutions should be engaged efficiently such as over sizing distribution...

A novel algorithm for seeking the maximumpower point of a photovoltaic (PV) array for any temperature and solar irradiation level, needing only the PV current value, is proposed. Satisfactory theoretical and experimental results are presented and were obtained when the algorithm was included on a 100 W 24 V PV buck converter prototype, using an inexpensive microcontroller. The load of the system used was a battery and a resistance. The main advantage of this new maximumpower point tracking (MPPT), when is compared with others, is that it only uses the measurement of the photovoltaic current, I{sub PV}. (author)

Full Text Available In this paper, a robust MaximumPower Point Tracking (MPPT for PV array has been proposed using sliding mode control by defining a new formulation for sliding surface which is based on increment conductance (INC method. The stability and robustness of the proposed controller are investigated to load variations and environment changes. Three different types of DC-DC converter are used in MaximumPower Point (MPP system and the results obtained are given. The simulation results confirm the effectiveness of the proposed method in the presence of load variations and environment changes for different types of DC-DC converter topologies.

In this keynote address, the author, who was acting president of AECL at the time of the conference, emphasizes the importance of nuclear energy to Canada, and its future importance to the developing countries. In 1992, nuclear energy supplied 15% of Canada's electricity, employed 30,000 people in Canada, created at least 10,000 jobs in other sectors, generated federal tax revenues of C$700 million, and by supplanting coal and gas imports saved about C$1 billion. Export sales prospects in China, Korea, Turkey, the Philippines, Indonesia and Thailand are indicated. AECL is presently undergoing reorganization for greater efficiency. A public opinion poll indicated about 70% Canadian public support for nuclear energy

The moderate increase of electrical energy demands (3% at present) can only be met by the parallel application of fossil and nuclear power plants and by electric power import via the transmission lines of the CMEA countries. The changes in the electrical energy and fuel demands and the development of the available capacities during the last 35 years are reviewed. The major purpose of Hungarian power economy is to save hydrocarbon fuels by taking advantages of power import opportunities by operating nuclear power plants at maximum capacity and the coal fired power stations at high capacity. The basic principles, the algorithm applied to optimize the load distribution of the electrical power system are discussed in detail with special attention to the role of nuclear power. The planned availability of nuclear power plants and the amount of electricity generated by nuclear plants should also be optimized. (V.N.)

As renewable generation has become less expensive during recent decades, and it becomes more accepted by the global population, the focus on renewable generation has expanded to include new types with promising future applications, such as river and tidal generation. Although the utilization of power electronics and electric machines in industry is phenomenal, the emphasis on system design is different for various sectors of industry. In precision control, robotics, and weaponry, the design emphasis is on accuracy and reliability with less concern for the cost of the final product. In energy generation, the cost of energy is the prime concern; thus, capital expenditures (CAPEX) and operations and maintenance expenditures (OPEX) are the major design objectives. This paper describes the electrical power conversion aspects of river and tidal generation. Although modern power converter control is available to control the generation side, the design was chosen on the bases of minimizing the CAPEX and OPEX; thus, the architecture is simple and modular for ease of replacement and maintenance. The power conversion is simplified by considering a simple diode bridge and a DC-DC power converter to take advantage of abundant and low-cost photovoltaic inverters that have well-proven grid integration characteristics (i.e., the capability to produce energy with good power quality and control real power and voltage on the grid side).

Full Text Available Due to Japan’s recent nuclear crisis and petroleum price hikes, the search for renewable energy sources has become an issue of immediate concern. A promising candidate attracting much global attention is solar energy, as it is green and also inexhaustible. A maximumpower point tracking (MPPT controller is employed in such a way that the output power provided by a photovoltaic (PV system is boosted to its maximum level. However, in the context of abrupt changes in irradiance, conventional MPPT controller approaches suffer from insufficient robustness against ambient variation, inferior transient response and a loss of output power as a consequence of the long duration required of tracking procedures. Accordingly, in this work the maximumpower point tracking is carried out successfully using a sliding mode extremum-seeking control (SMESC method, and the tracking performances of three controllers are compared by simulations, that is, an extremum-seeking controller, a sinusoidal extremum-seeking controller and a sliding mode extremum-seeking controller. Being able to track the maximumpower point promptly in the case of an abrupt change in irradiance, the SMESC approach is proven by simulations to be superior in terms of system dynamic and steady state responses, and an excellent robustness along with system stability is demonstrated as well.

Full Text Available In order to deliver the maximum available power to the load under the condition of varying solar irradiation and environment temperature, maximumpower point tracking (MPPT technologies have been used widely in PV systems. Among all the MPPT schemes, the chaos method is one of the hot topics in recent years. In this paper, a novel two-stage chaos optimization method is presented which can make search faster and more effective. In the process of proposed chaos search, the improved logistic mapping with the better ergodic is used as the first carrier process. After finding the current optimal solution in a certain guarantee, the power function carrier as the secondary carrier process is used to reduce the search space of optimized variables and eventually find the maximumpower point. Comparing with the traditional chaos search method, the proposed method can track the change quickly and accurately and also has better optimization results. The proposed method provides a new efficient way to track the maximumpower point of PV array.

The coolant heat sinks in thermoelectric generators (TEG) play an important role in order to powergeneration in the energy systems. This paper explores the effective pumping power required for the TEGs cooling at five temperature difference of the hot and cold sides of the TEG. In addition......, the temperature distribution and the pressure drop in sample microchannels are considered at four sample coolant flow rates. The heat sink contains twenty plate-fin microchannels with hydraulic diameter equal to 0.93 mm. The experimental results show that there is a unique flow rate that gives maximum net-power...

Utilities are encouraged to participate in the effort to explore and develop adequate supplies of uranium in order to assure a high level of effort and have some control over production rates. Regulatory commissions are likewise encouraged to be receptive to utility initiatives by granting assurances of favorable rate treatment to cover investments. Confusion arises over the difference between forward coverage based on proven reserves of commercial-grade uranium and long-range availability based on potential resources. Cancellations and delays in the licensing of nuclear power plants have made it difficult for uranium suppliers to proceed with confidence. Drilling difficulties and the short productive life of most uranium mines will probably keep proven reserve levels lower than long-term plant requirements. Several approaches are outlined for developing uranium reserve estimates. ERDA projections are based on ''favorable ground'' areas where uranium deposits are most probable. It is assumed that, where a market exists, minerals will be extracted and traditional procurement methods will evolve. Since utilities are the only industry committed to a viable fuel cycle, they are justified in joining in the search for supplies

The role and the general characteristics of steam generators in nuclear power plants are indicated, and particular types are described according to the coolant nature (carbon dioxide, helium, light water, heavy water, sodium) [fr

Developing nations use the nuclear plant option to satisfy important overall national development objectives, in addition to providing economical electric power. The relative importance of these two objectives changes as the nuclear program develops and the interim milestones are reached. This paper describes the three typical stages of nuclear power development programs. The first and the second generations are development phases with the third generation reaching self sufficiency. Examples are presented of European and Far East countries or regions which have reached of are about to step into the third generation phase of development. The paper concludes that to achieve the objective of a nuclear power self sufficiency, other than merely filling the need of economical electric power, a careful technology transfer plan must be followed which sets realistic and achievable goals and establishes the country as a reliable and technically competent member of the nuclear power industry. (author)

Developing nations use the nuclear plant option to satisfy important overall national development objectives, in addition to providing economical electric power. The relative importance of these two objectives changes as the nuclear program develops and the interim milestones are reached. This paper describes the three typical stages of nuclear power development programs. The first and the second generations are development phases with the third generation reaching self sufficiency. Examples are presented of European and Far East countries or regions which have reached or are about to step into the third generation phase of development. The paper concludes that to achieve the objectives of a nuclear power self sufficiency, other than merely filling the need of economical electric power, a careful technology transfer plan must be followed which sets realistic and achievable goals and establishes the country as a reliable and technically competent member of the nuclear power industry

Full Text Available Finding new energy sources is an important challenge of our times. A lot of research focuses on identifying such sources that can also be exploited with relatively simple and efficient systems. These sources can be either new materials that can be used to generate energy, or solutions to scavenge already existing forms of energy. Part of the latter class of solutions, the system presented in this paper converts the energy consumed by many people in gyms (or even at home, during exercise into electric energy. This energy exists anyway, because people want to be healthier or to look better. Currently, this significant (in our opinion amount of energy is actually wasted and transformed into heat. Instead, in this study, a prototype scavenging system (dedicated to fitness/stationary bikes to collect and (reuse this energy is presented. Specifically, we depict the design of a low-budget system that uses existing, discrete components and is able to scavenge some of the energy spent by the biker. The experimental results show that the system is functional, but its efficiency is limited by (mechanical losses before the collection.

In the recent years, the solar energy becomes one of the most important alternative sources of electric energy, so it is important to improve the efficiency and reliability of the photovoltaic (PV) systems. Maximumpower point tracking (MPPT) plays an important role in photovoltaic power systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize their array efficiency. This paper presents a maximumpower point tracker (MPPT) using Fuzzy Logic theory for a PV system. The work is focused on the well known Perturb and Observe (P&O) algorithm and is compared to a designed fuzzy logic controller (FLC). The simulation work dealing with MPPT controller; a DC/DC Ćuk converter feeding a load is achieved. The results showed that the proposed Fuzzy Logic MPPT in the PV system is valid.

Full Text Available In the recent years, the solar energy becomes one of the most important alternative sources of electric energy, so it is important to improve the efficiency and reliability of the photovoltaic (PV systems. Maximumpower point tracking (MPPT plays an important role in photovoltaic power systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize their array efficiency. This paper presents a maximumpower point tracker (MPPT using Fuzzy Logic theory for a PV system. The work is focused on the well known Perturb and Observe (P&O algorithm and is compared to a designed fuzzy logic controller (FLC. The simulation work dealing with MPPT controller; a DC/DC Ćuk converter feeding a load is achieved. The results showed that the proposed Fuzzy Logic MPPT in the PV system is valid.

Since mechanical loads exert a significant influence on the life span of wind turbines, the reduction of transient load on drive-train shaft has received more attention when implementing a maximumpower point tracking(MPPT) controller.Moreover, a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue. However, for the existing control strategies based on nonlinear model of wind turbines, the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft. Hence, in this paper, a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously. Then,simulations on FAST(Fatigue, Aerodynamics, Structures, and Turbulence) code and experiments on the wind turbine simulator(WTS) based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load.

Since mechanical loads exert a significant influence on the life span of wind turbines,the reduction of transient load on drive-train shaft has received more attention when implementing a maximumpower point tracking (MPPT) controller.Moreover,a trade-off between the efficiency of wind energy extraction and the load level of drive-train shaft becomes a key issue.However,for the existing control strategies based on nonlinear model of wind turbines,the MPPT efficiencies are improved at the cost of the intensive fluctuation of generator torque and significant increase of transient load on drive train shaft.Hence,in this paper,a nonlinear controller with variable parameter is proposed for improving MPPT efficiency and mitigating transient load on drive-train simultaneously.Then,simulations on FAST (Fatigue,Aerodynamics,Structures,and Turbulence) code and experiments on the wind turbine simulator (WTS) based test bench are presented to verify the efficiency improvement of the proposed control strategy with less cost of drive-train load.

The factors that limit both the continuous wave (CW) and the pulsed output power of broad-area laser diodes driven at very high currents are investigated theoretically and experimentally. The decrease in the gain due to self-heating under CW operation and spectral holeburning under pulsed operation, as well as heterobarrier carrier leakage and longitudinal spatial holeburning, are the dominant mechanisms limiting the maximum achievable output power.

The characteristic data of tokamaks optimized with respect to their power density or wall load are determined. Reactor relevant constraints are imposed, such as a fixed plant net power output, a fixed blanket thickness and the dependence of the maximum toroidal field on the geometry and conductor material. The impact of finite burn times is considered. Various scaling laws of the toroidal beta with the aspect ratio are discussed. (orig.) 891 GG/orig. 892 RDG [de

As the energy sector shifts and changes to focus on renewable technologies, the optimization of wind power becomes a key practical issue. Reactive Power Management of Power Networks with Wind Generation brings into focus the development and application of advanced optimization techniques to the study, characterization, and assessment of voltage stability in power systems. Recent advances on reactive power management are reviewed with particular emphasis on the analysis and control of wind energy conversion systems and FACTS devices. Following an introduction, distinct chapters cover the 5 key

I am going to talk about pulsed high-power rf generation for normal-conducting electron and positron linacs suitable for applications to high-energy physics in the Next Linear Collider, or NLC. The talk will cover some basic rf system design issues, klystrons and other microwave power sources, rf pulse-compression devices, and test facilities for system-integration studies

1, 4 DEPARTMENT OF SYSTEMS ENGINEERING, UNIVERSITY OF LAGOS, AKOKA, YABA, ... pumped storage system for generating hydroelectric power all year round. ... Power supply situation in Nigeria has no doubt ..... (objective functions), criteria for evaluation of control .... adsen H “Para eter esti ation in distributed.

Abstract—The paper presents the innovative technology of highaltitude wind powergeneration, indicated as Kitenergy, which exploits the automatic flight of tethered airfoils (e.g., power kites) to extract energy from wind blowing between 200 and 800 m above the ground. The key points of this

An improved thermal power plant and method of powergeneration is described which minimizes thermal stress and chemical impurity buildup in the vaporizing component, particularly beneficial under loss of normal feed fluid and startup conditions. The invention is particularly applicable to a liquid metal fast breeder reactor plant

Recently, photovoltaic (PV) generation is becoming increasingly popular in industrial applications. As a renewable and alternative source of energy they feature superior characteristics such as being clean and silent along with less maintenance problems compared to other sources of the energy. In PV generation, employing a MaximumPower Point Tracking (MPPT) method is essential to obtain the maximum available solar energy. Among several proposed MPPT techniques, the Perturbation and Observation (P&O;) and Model Predictive Control (MPC) methods are adopted in this work. The components of the MPPT control system which are P&O; and MPC algorithms, PV module and high gain DC-DC boost converter are simulated in MATLAB Simulink. They are evaluated theoretically under rapidly and slowly changing of solar irradiation and temperature and their performance is shown by the simulation results, finally a comprehensive comparison is presented.

Nuclear powergeneration has undergone major expansion and developments in recent years; this third edition contains much revised material in presenting the state-of-the-art of nuclear power station designs currently in operation throughout the world. The volume covers nuclear physics and basic technology, nuclear station design, nuclear station operation, and nuclear safety. Each chapter is independent but with the necessary technical overlap to provide a complete work on the safe and economic design and operation of nuclear power stations.

Extraction of maximumpower from PV (Photovoltaic) cell is necessary to make the PV system efficient. Maximumpower can be achieved by operating the system at MPP (MaximumPower Point) (taking the operating point of PV panel to MPP) and for this purpose MPPT (MaximumPower Point Trackers) are used. There are many tracking algorithms/methods used by these trackers which includes incremental conductance, constant voltage method, constant current method, short circuit current method, PAO (Perturb and Observe) method, and open circuit voltage method but PAO is the mostly used algorithm because it is simple and easy to implement. PAO algorithm has some drawbacks, one is low tracking speed under rapid changing weather conditions and second is oscillations of PV systems operating point around MPP. Little improvement is achieved in past papers regarding these issues. In this paper, a new method named 'Decrease and Fix' method is successfully introduced as improvement in PAO algorithm to overcome these issues of tracking speed and oscillations. Decrease and fix method is the first successful attempt with PAO algorithm for stability achievement and speeding up of tracking process in photovoltaic system. Complete standalone photovoltaic system's model with improved perturb and observe algorithm is simulated in MATLAB Simulink. (author)

A lateral bias has been previously reported in dance training. The aim of this study was to investigate whether there are any bilateral differences in peak forces, power, and maximum knee flexion during a sequence of three grand jetes and how they relate to leg dominance. A randomised observational

An advanced power control strategy by limiting the maximum feed-in power of PV systems has been proposed, which can ensure a fast and smooth transition between maximumpower point tracking and Constant PowerGeneration (CPG). Regardless of the solar irradiance levels, high-performance and stable...... operation are always achieved by the proposed control strategy. It can regulate the PV output power according to any set-point, and force the PV systems to operate at the left side of the maximumpower point without stability problems. Experimental results have verified the effectiveness of the proposed CPG...

The objective of this research was to study the effect of turbine materials on powergeneration efficiency from the water free vortex hydro power plant made of steel and aluminium. These turbines consisted of five blades and were twisted with angles along the height of water. These blades were the maximum width of 45 cm. and height of 32 cm. These turbines were made and experimented for the water free vortex hydro power plant in the laboratory with the water flow rate of 0.68, 1.33, 1.61, 2.31, 2.96 and 3.63 m 3 /min and an electrical load of 20, 40, 60, 80 and 100 W respectively. The experimental results were calculated to find out the torque, electric power, and electricity production efficiency. From the experiment, the results showed that the maximumpowergeneration efficiency of steel and aluminium turbine were 33.56% and 34.79% respectively. From the result at the maximum water flow rate of 3.63 m 3 /min, it was found that the torque value and electricity production efficiency of aluminium turbine was higher than that of steel turbine at the average of 8.4% and 8.14%, respectively. This result showed that light weight of water turbine can increase the torque and powergeneration efficiency. (paper)

Full Text Available The latest forecasts on the upcoming effects of climate change are leading to a change in the worldwide power production model, with governments promoting clean and renewable energies, as is the case of tidal energy. Nevertheless, it is still necessary to improve the efficiency and lower the costs of the involved processes in order to achieve a Levelized Cost of Energy (LCoE that allows these devices to be commercially competitive. In this context, this paper presents a novel complementary control strategy aimed to maximize the output power of a Tidal Stream Turbine (TST composed of a hydrodynamic turbine, a Doubly-Fed Induction Generator (DFIG and a back-to-back power converter. In particular, a global control scheme that supervises the switching between the two operation modes is developed and implemented. When the tidal speed is low enough, the plant operates in variable speed mode, where the system is regulated so that the turbo-generator module works in maximumpower extraction mode for each given tidal velocity. For this purpose, the proposed back-to-back converter makes use of the field-oriented control in both the rotor side and grid side converters, so that a maximumpower point tracking-based rotational speed control is applied in the Rotor Side Converter (RSC to obtain the maximumpower output. Analogously, when the system operates in power limitation mode, a pitch angle control is used to limit the power captured in the case of high tidal speeds. Both control schemes are then coordinated within a novel complementary control strategy. The results show an excellent performance of the system, affording maximumpower extraction regardless of the tidal stream input.

In Sweden, nuclear powergeneration was received initially favorably. In the end of 1960s, however, nuclear powergeneration got involved in the activities of environment preservation. Then, political parties became opposed to nuclear powergeneration, and now, the need of nuclear powergeneration itself is regarded as questionable. In the general election in 1976, the Government opposing the nuclear powergeneration won. As the result, the conditional nuclear power development law and the energy committee were set up. The committee composed of parliament members, experts, and representatives of enterprises and trade unions is to submit its report so that the parliament can prepare a new energy program in the fall of 1978. Meanwhile, the nuclear fuel safety project formed newly has studied to satisfy the conditions of the law. In Sweden, which has developed nuclear reactors independently from the technology of USA, the oppositions are on the decrease, however. It is awaited what decision will be made by the Government in this fall.

A generic method for the providing of prediction intervals of wind powergeneration is described. Prediction intervals complement the more common wind power point forecasts, by giving a range of potential outcomes for a given probability, their so-called nominal coverage rate. Ideally they inform...... on the characteristics of prediction errors for providing conditional interval forecasts. By simultaneously generating prediction intervals with various nominal coverage rates, one obtains full predictive distributions of wind generation. Adapted resampling is applied here to the case of an onshore Danish wind farm...... to the case of a large number of wind farms in Europe and Australia among others is finally discussed....

The proportion of nuclear power in the total generated electric power has been increasing year after year, and the ensuring of its stable supply has been demanded. For the further development of nuclear powergeneration, the heightening of economical efficiency which is the largest merit of nuclear power and the public acceptance as a safe and stable electric power source are the important subjects. In order to solve these subjects, in nuclear powergeneration, various automation techniques have been applied for the purpose of the heightening of reliability, labor saving and the reduction of radiation exposure. Meeting the high needs of automation, the automation technology aided by computers have been applied to the design, manufacture and construction, operation and maintenance of nuclear power plants. Computer-aided design and the examples of design of a reactor building, pipings and a fuel assembly, an automatic welder for pipings of all position TIG welding type, a new central monitoring and control system, an automatic exchanger of control rod-driving mechanism, an automatic in-service inspection system for nozzles and pipings, and a robot for steam generator maintenance are shown. The trend of technical development and an intelligent moving robot, a system maintenance robot and a four legs walking robot are explained. (Kako, I.)

In recent years, there has been active research on exhaust gas waste heat energy recovery for automobiles. Meanwhile, the use of solar energy is also proposed to promote on-board renewable energy and hence to improve their fuel economy. In this paper, a new thermoelectric-photovoltaic (TE-PV) hybrid energy system is proposed and implemented for automobiles. The key is to newly develop the power conditioning circuit using maximumpower point tracking so that the output power of the proposed TE-PV hybrid energy system can be maximized. An experimental system is prototyped and tested to verify the validity of the proposed system.

In this work we report on the design and realization of a maximumpower point tracking (MPPT) circuit suitable for low power, portable applications with resistive load. The design rules included cost, size and power efficiency considerations. A novel scheme for the implementation of the control loop of the MPPT circuit is proposed, combining good performance with compact design. The operation and performances were simulated at circuit schematic level with simulation program with integrated circuit emphasis (SPICE). The improved operation of a PV system using our MPPT circuit was demonstrated using a purely resistive load. (author)

This paper presents power coordination, powergeneration, and power flow control schemes for supply-demand balance in distributed grid networks. Consensus schemes using only local information are employed to generatepower coordination, powergeneration and power flow control signals. For the supply-demand balance, it is required to determine the amount of power needed at each distributed power node. Also due to the different powergeneration capacities of each power node, coordination of pow...

This article discusses the certification of powergenerated from sewage gas in packaged co-generation units in Switzerland. Since 2003, such electricity can be sold as 'green power' to consumers, who pay an additional charge for this ecologically generatedpower. Since the eco-balance of this electricity generated in wastewater treatment plant is considered as being excellent, the prestigious 'Naturemade Star' label has been awarded to it. This label sets most stringent requirements. The Canius wastewater treatment plant in the 'Lenzerheide' in eastern Switzerland is taken as an example to illustrate the procedure that has to be gone through to receive certification. This certification is carried out by independent auditors and guarantees that the 'green' electricity offered by the utility meets the high ecological criteria set by the label

The invention relates to a steam cycle electric energy generating plants of the type comprising a fossil or nuclear fuel boiler for generating steam and a turbo alternator group, the turbine of which is fed by the boiler steam. The improvement is characterized in that use is made of a second energy generating group in which a fluid (e.g. ammoniac) undergoes a condensation cycle the heat source of said cycle being obtained through a direct or indirect heat exchange with a portion of the boiler generated steam whereby it is possible without overloading the turbo-alternator group, to accomodate any increase of the boiler power resulting from the use of another fuel while maintaining a maximum energy output. This can be applied to electric power stations [fr

The Deep Space Avionics (DSA) Project is developing a new generation of power system building blocks. Using application specific integrated circuits (ASICs) and power switching modules a scalable power system can be constructed for use on multiple deep space missions including future missions to Mars, comets, Jupiter and its moons. The key developments of the DSA power system effort are five power ASICs and a mod ule for power switching. These components enable a modular and scalab le design approach, which can result in a wide variety of power syste m architectures to meet diverse mission requirements and environments . Each component is radiation hardened to one megarad) total dose. The power switching module can be used for power distribution to regular spacecraft loads, to propulsion valves and actuation of pyrotechnic devices. The number of switching elements per load, pyrotechnic firin gs and valve drivers can be scaled depending on mission needs. Teleme try data is available from the switch module via an I2C data bus. The DSA power system components enable power management and distribution for a variety of power buses and power system architectures employing different types of energy storage and power sources. This paper will describe each power ASIC#s key performance characteristics as well a s recent prototype test results. The power switching module test results will be discussed and will demonstrate its versatility as a multip urpose switch. Finally, the combination of these components will illu strate some of the possible power system architectures achievable fro m small single string systems to large fully redundant systems.

Solar energy is a popular renewable energy source for the future because it does not produce any pollution. In addition, it is unlimited and a clean source of energy. This paper discussed a photovoltaic solar fan system that could be used inside the house with the potential of cooling the indoor temperature. The solar cell module is located at the eaves of the house and could block the sunlight directly into the house, and convert solar power into electric power through the battery. The paper described software implementation and hardware circuit design in detail. The paper also illustrated a different algorithm to calculate the maximumpower point regulation. The conventional algorithm calculates the solar cell module output power by multiplying the input voltage and input current for the solar cell module directly. By changing the input voltage variable into duty variable, the voltage sensor is not required under the proposed scheme. Only the duty and current variables are needed to calculate the maximumpower. The microchip dsPIC microcontroller was used to implement the algorithm. Different DC link levels were verified and implemented for comparison. It was concluded that the characteristics of the solar cell module could be measured automatically, and the maximumpower point could be guaranteed by the proposed algorithm. 9 refs., 6 tabs., 14 figs.

In this paper, an improved auto-scaling variable step-size MaximumPower Point Tracking (MPPT) method for photovoltaic (PV) system was proposed. To achieve simultaneously a fast dynamic response and stable steady-state power, a first improvement was made on the step-size scaling function of the duty cycle that controls the converter. An algorithm was secondly proposed to address wrong decision that may be made at an abrupt change of the irradiation. The proposed auto-scaling variable step-size approach was compared to some various other approaches from the literature such as: classical fixed step-size, variable step-size and a recent auto-scaling variable step-size maximumpower point tracking approaches. The simulation results obtained by MATLAB/SIMULINK were given and discussed for validation.

This paper presents a new maximumpower point tracking control for photovoltaic (PV) panels. The control can be categorized into the Perturb and Observe (P & O) method. It utilizes instantaneous voltage ripples at PV panel output terminals caused by the switching of a chopper connected to the panel in order to identify the direction for the maximumpower point (MPP). The tracking for the MPP is achieved by a feedback control of the average terminal voltage of the panel. Appropriate use of the instantaneous and the average values of the PV voltage for the separate purposes enables both the quick transient response and the good convergence with almost no ripples simultaneously. The tracking capability is verified experimentally with a 2.8 W PV panel under a controlled experimental setup. A numerical comparison with a conventional P & O confirms that the proposed control extracts much more power from the PV panel.

Full Text Available This paper presents an improved maximumpower point tracking (MPPT algorithm using a fuzzy logic controller (FLC in order to extract potential maximumpower from photovoltaic cells. The objectives of the proposed algorithm are to improve the tracking speed, and to simultaneously solve the inherent drawbacks such as slow tracking in the conventional perturb and observe (P and O algorithm. The performances of the conventional P and O algorithm and the proposed algorithm are compared by using MATLAB/Simulink in terms of the tracking speed and steady-state oscillations. Additionally, both algorithms were experimentally validated through a digital signal processor (DSP-based controlled-boost DC-DC converter. The experimental results show that the proposed algorithm performs with a shorter tracking time, smaller output power oscillation, and higher efficiency, compared with the conventional P and O algorithm.

Full Text Available In this paper a new maximumpower point tracking method based on fuzzy sliding mode control is proposed, and employed in a PV water pumping system based on a DC-DC boost converter, to produce maximumpower from the solar panel hence more speed in the DC motor and more water quantity. This method combines two different tracking techniques sliding mode control and fuzzy logic; our controller is based on sliding mode control, then to give better stability and enhance the power production a fuzzy logic technique was added. System modeling, sliding method definition and the new control method presentation are represented in this paper. The results of the simulation that are compared to both sliding mode controller and perturbation and observation method demonstrate effectiveness and robustness of the proposed controller.

Full Text Available Maximumpower point trackers (MPPTs play an essential role in extracting power from photovoltaic (PV panels as they make the solar panels to operate at the maximumpower point (MPP whatever the changes of environmental conditions are. For this reason, they take an important place in the increase of PV system efficiency. MPPTs are driven by MPPT algorithms and a number of MPPT algorithms are proposed in the literature. The comparison of the MPPT algorithms in literature are made by a sun simulator based test system under laboratory conditions for short durations. However, in this study, the performances of four most commonly used MPPT algorithms are compared under real environmental conditions for longer periods. A dual identical experimental setup is designed to make a comparison between two the considered MPPT algorithms as synchronized. As a result of this study, the ranking among these algorithms are presented and the results show that Incremental Conductance (IC algorithm gives the best performance.

Full Text Available In photovoltaic (PV system applications, it is very important to design a system for operating of the solar cells (SCs under best conditions and highest efficiency. Maximumpower point (MPP varies depending on the angle of sunlight on the surface of the panel and cell temperature. Hence, the operating point of the load is not always MPP of PV system. Therefore, in order to supply reliable energy to the load, PV systems are designed to include more than the required number of modules. The solution to this problem is that switching power converters are used, that is called maximumpower point tracker (MPPT. In this study, the various aspects of these algorithms have been analyzed in detail. Classifications, definitions, and basic equations of the most widely used MPPT technologies are given. Moreover, a comparison was made in the conclusion.

Full Text Available This paper presents a new design method of asymmetrical relay resonators for maximum wireless power transfer. A new design method for relay resonators is demanded because maximumpower transfer efficiency (PTE is not obtained at the resonant frequency of unit resonator. The maximum PTE for relay resonators is obtained at the different resonances of unit resonator. The optimum design of asymmetrical relay is conducted by both the optimum placement and the optimum capacitance of resonators. The optimum placement is found by scanning the positions of the relays and optimum capacitance can be found by using genetic algorithm (GA. The PTEs are enhanced when capacitance is optimally designed by GA according to the position of relays, respectively, and then maximum efficiency is obtained at the optimum placement of relays. The capacitance of the second resonator to nth resonator and the load resistance should be determined for maximum efficiency while the capacitance of the first resonator and the source resistance are obtained for the impedance matching. The simulated and measured results are in good agreement.

We investigate the effect of the electric field maximum on the Rabi flopping and the generated higher frequency spectra properties by solving Maxwell-Bloch equations without invoking any standard approximations. It is found that the maximum of the electric field will lead to carrier-wave Rabi flopping (CWRF) through reversion dynamics which will be more evident when the applied field enters the sub-one-cycle regime. Therefore, under the interaction of sub-one-cycle pulses, the Rabi flopping follows the transient electric field tightly through the oscillation and reversion dynamics, which is in contrast to the conventional envelope Rabi flopping. Complete or incomplete population inversion can be realized through the control of the carrier-envelope phase (CEP). Furthermore, the generated higher frequency spectra will be changed from distinct to continuous or irregular with the variation of the CEP. Our results demonstrate that due to the evident maximum behavior of the electric field, pulses with different CEP give rise to different CWRFs, and then different degree of interferences lead to different higher frequency spectral features.

Attention is paid to the economics of import of biomass to the Netherlands, and subsequent utilisation for powergeneration, as a means to reduce dependence on (imported) fossil fuels and to reduce CO2 emission. Import of wood to the extent of 40 PJ or more from Baltic and South American states seems to be readily achievable. Import of biomass has various advantages, not only for the European Union (reduced CO2 emissions) but also for the countries of origin (employment creation). However, possible disadvantages or risks should be taken into account. With that in mind, import of biomass from Baltic states seems very interesting, although it should be noted that in some of those countries the alternative of fuel-switching to biomass seems to be more cost-effective than import of biomass from those countries. Given the expected increase in inland biomass consumption in the Baltic countries and the potential substantial future demand for biomass in other Western European countries it is expected that the biomass supply from Baltic countries will not be sufficient to fulfill the demand. An early focus on import from other countries seems advisable. Several powergeneration options are available with short to medium term potential and long term potential. The margin between costs of biomass-fuelled power and of coal fired power will be smaller, due to substantial improvements in powergenerating efficiency and reductions of investment costs of options for powergeneration from biomass, notably Biomass Gasification Combined Cycle. 18 refs

Full Text Available The rural electrification is characterized by geographical dispersion of the population, low consumption, high investment by consumers and high cost. Moreover, solar radiation constitutes an inexhaustible source of energy and in its conversion into electricity photovoltaic panels are used. In this study, equations were adjusted to field conditions presented by the manufacturer for current and power of small photovoltaic systems. The mathematical analysis was performed on the photovoltaic rural system I-100 from ISOFOTON, with power 300 Wp, located at the Experimental Farm Lageado of FCA/UNESP. For the development of such equations, the circuitry of photovoltaic cells has been studied to apply iterative numerical methods for the determination of electrical parameters and possible errors in the appropriate equations in the literature to reality. Therefore, a simulation of a photovoltaic panel was proposed through mathematical equations that were adjusted according to the data of local radiation. The results have presented equations that provide real answers to the user and may assist in the design of these systems, once calculated that the maximumpower limit ensures a supply of energy generated. This real sizing helps establishing the possible applications of solar energy to the rural producer and informing the real possibilities of generating electricity from the sun.A eletrificação rural é caracterizada pela dispersão geográfica da população, baixo consumo, alto investimento por consumidor e elevado custo operacional. Por outro lado, a radiação solar constitui-se numa inesgotável fonte energética, e para sua conversão em energia elétrica são utilizados painéis fotovoltaicos. Neste trabalho, foram determinadas equações ajustadas às condições de campo apresentadas pelo fabricante para corrente e potência de sistemas fotovoltaicos de pequeno porte. A análise matemática foi feita sobre o sistema fotovoltaico rural I-100 da

Optimal Velocity to Achieve MaximumPower Output – Bench Press for Trained Footballers In today’s world of strength training there are many myths surrounding effective exercising with the least possible negative effect on one’s health. In this experiment we focus on the finding of a relationship between maximum output, used load and the velocity with which the exercise is performed. The main objective is to find the optimal speed of the exercise motion which would allow us to reach the ma...

Recently, a study investigated the feasibility of a large, 60 GeV accelerator. This paper presents the conceptual design of the magnet power supply (PS() and energy storage system. The main ring magnets are supplied by six, high-voltage and two, low-voltage power supplies. These power supplies drive a trapezoidal shaped current wave through the magnets. The peak current is 10 kA and the repetition frequency is 3.3 Hz. During the acceleration period the current is increased from 1040 A to 10,000 A within 50 msec which requires a loop voltage of 120 kV and a peak power of 1250 MW. During the reset period, the PS operates as an inverter with a peak power of -1250 MW. The large energy fluctuation necessitates the use of a storage generator. Because of the relatively high operation frequency, this generator operates in a transient mode which significantly increases the rotor current and losses. The storage generator is directly driven by a variable speed drive, which draws a practically constant power of 17 MW from the ac supply network and eliminates the pulse loading. For the reduction of dc ripple, the power supplies operate in a 24 pulse mode

The finite electrode size effects on the performance of an infinitely long MHD powergeneration duct are calculated by means of conformal mapping. The general conformal transformation is deduced and applied in a graphic way. The analysis includes variations in the segmentation degree, the Hall parameter of the gas and the electrode/insulator length ratio as well as the influence of the external circuitry and loading. A general criterion for a minimum of the generator internal resistance is given. The same criterion gives the conditions for the occurrence of internal current leakage between adjacent electrodes. It is also shown that the highest power output at a prescribed efficiency is always obtained when the current is made to flow between exactly opposed electrodes. Curves are presented showing the power-efficiency relations and other generator properties as depending on the segmentation degree and the Hall parameter in the cases of axial and transverse power extraction. The implications of limiting the current to flow between a finite number of identical electrodes are introduced and combined with the condition for current flow between opposed electrodes. The characteristics of generators with one or a few external loads can then be determined completely and examples are given in a table. It is shown that the performance of such generators must not necessarily be inferior to that of segmented generators with many independent loads. However, the problems of channel end losses and off-design loading have not been taken into consideration.

the possibilities for integration of even more wind power using new power balancing strategies that exploit the possibilities given by the existence of CHP plants as well as the impact of heat pumps for district heating. The analyses demonstrate that it is possible to accommodate 50% or more wind power without......Denmark has the World?s highest penetration of wind power in electricity generation with a share of 15.0% of total domestic demand in 2002 (DEA, 2004). This is unevenly distributed in the two electricity systems of Denmark giving a share as high as 20.7% in Western Denmark in 2003 up from 18...... power balancing strategies are not applied, costly grid expansions will follow expansions in installed wind power capacity....

Full Text Available Photovoltaic (PV systems have non-linear characteristics that generatemaximumpower at one particular operating point. Environmental factors such as irradiance and temperature variations greatly affect the maximumpower point (MPP. Diverse offline and online techniques have been introduced for tracking the MPP. Here, to track the MPP, an augmented-state feedback linearized (AFL non-linear controller combined with an artificial neural network (ANN is proposed. This approach linearizes the non-linear characteristics in PV systems and DC/DC converters, for tracking and optimizing the PV system operation. It also reduces the dependency of the designed controller on linearized models, to provide global stability. A complete model of the PV system is simulated. The existing maximumpower-point tracking (MPPT and DC/DC boost-converter controller techniques are compared with the proposed ANN method. Two case studies, which simulate realistic circumstances, are presented to demonstrate the effectiveness and superiority of the proposed method. The AFL with ANN controller can provide good dynamic operation, faster convergence speed, and fewer operating-point oscillations around the MPP. It also tracks the global maxima under different conditions, especially irradiance-mutating situations, more effectively than the conventional methods. Detailed mathematical models and a control approach for a three-phase grid-connected intelligent hybrid system are proposed using MATLAB/Simulink.

Full Text Available This study first explored the effect of shading on the output characteristics of modules in a photovoltaic module array. Next, a modified particle swarm optimization (PSO method was employed to track the maximumpower point of the multiple-peak characteristic curve of the array. Through the optimization method, the weighting value and cognition learning factor decreased with an increasing number of iterations, whereas the social learning factor increased, thereby enhancing the tracking capability of a maximumpower point tracker. In addition, the weighting value was slightly modified on the basis of the changes in the slope and power of the characteristic curve to increase the tracking speed and stability of the tracker. Finally, a PIC18F8720 microcontroller was coordinated with peripheral hardware circuits to realize the proposed PSO method, which was then adopted to track the maximumpower point of the power–voltage (P–V output characteristic curve of the photovoltaic module array under shading. Subsequently, tests were conducted to verify that the modified PSO method exhibited favorable tracking speed and accuracy.

Highlights: → The FOICM can shorten the tracking time less than traditional methods. → The proposed method can work under lower solar radiation including thin and heavy clouds. → The FOICM algorithm can achieve MPPT for radiation and temperature changes. → It is easy to implement in a single-chip microcontroller or embedded system. -- Abstract: This paper proposes maximum photovoltaic power tracking (MPPT) for the photovoltaic (PV) array using the fractional-order incremental conductance method (FOICM). Since the PV array has low conversion efficiency, and the output power of PV array depends on the operation environments, such as various solar radiation, environment temperature, and weather conditions. Maximum charging power can be increased to a battery using a MPPT algorithm. The energy conversion of the absorbed solar light and cell temperature is directly transferred to the semiconductor, but electricity conduction has anomalous diffusion phenomena in inhomogeneous material. FOICM can provide a dynamic mathematical model to describe non-linear characteristics. The fractional-order incremental change as dynamic variable is used to adjust the PV array voltage toward the maximumpower point. For a small-scale PV conversion system, the proposed method is validated by simulation with different operation environments. Compared with traditional methods, experimental results demonstrate the short tracking time and the practicality in MPPT of PV array.

1 - Description of program or function: LPGC is a set of nine microcomputer programs for estimating powergeneration costs for large steam-electric power plants. These programs permit rapid evaluation using various sets of economic and technical ground rules. The levelized powergeneration costs calculated may be used to compare the relative economics of nuclear and coal-fired plants based on life-cycle costs. Cost calculations include capital investment cost, operation and maintenance cost, fuel cycle cost, decommissioning cost, and total levelized powergeneration cost. These programs can be used for quick analyses of powergeneration costs using alternative economic parameters, such as interest rate, escalation rate, inflation rate, plant lead times, capacity factor, fuel prices, etc. The two major types of electric generating plants considered are pressurized-water reactor (PWR) and pulverized coal-fired plants. Data are also provided for the Large Scale Prototype Breeder (LSPB) type liquid metal reactor. Costs for plant having either one or two units may be obtained. 2 - Method of solution: LPGC consists of nine individual menu-driven programs controlled by a driver program, MAINPWR. The individual programs are PLANTCAP, for calculating capital investment costs; NUCLOM, for determining operation and maintenance (O and M) costs for nuclear plants; COALOM, for computing O and M costs for coal-fired plants; NFUEL, for calculating levelized fuel costs for nuclear plants; COALCOST, for determining levelized fuel costs for coal-fired plants; FCRATE, for computing the fixed charge rate on the capital investment; LEVEL, for calculating levelized powergeneration costs; CAPITAL, for determining capitalized cost from overnight cost; and MASSGEN, for generating, deleting, or changing fuel cycle mass balance data for use with NFUEL. LPGC has three modes of operation. In the first, each individual code can be executed independently to determine one aspect of the total

Perturb and observe best operation conditions were investigated in order to identify edge efficiency performance capabilities of a maximumpower point (MPP) tracking technique for photovoltaic (PV) applications. The strategy was developed to ensure a 3-points behavior across the MPP under a fixed irradiation level with a central point blocked on the MPP and 2 operating points operating at voltage values that guaranteed the same power levels. The system was also devised to quickly detect the MPP movement in the presence of varying atmospheric conditions by increasing the perturbation so that the MPP was guaranteed within a few sampling periods. A perturbation equation was selected where amplitude was represented as a function of the actual power drawn from the PV field together with the adoption of a parabolic interpolation of the sequence of the final 3 acquired voltage power couples corresponding to as many operating points. The technique was developed to ensure that the power difference between 2 consecutive operating points was higher than the power quantization error. Simulations were conducted to demonstrate that the proposed technique arranged operating points symmetrically around the MPP. The average power of the 3-points set was achieved by means of the parabolic prediction. Experiments conducted to validate the simulation showed a reduced power oscillation below the MPP and a real power gain. 2 refs., 8 figs.

This report for the Swiss Federal Office of Energy (SFOE) presents expert opinion on the question of how Switzerland could meet its demands for power in the future. The results of the analysis of two options - the import of electrical power or its generation using natural-gas-fired power stations - made in the light of gas market liberalisation are presented. These include the assessment of the use of 'GuD' (combined gas and steam-turbine) power stations in the 100 MW e l to 400 MW e l class regarding their cost, their emissions and primary energy consumption. The authors discuss the assessments from the political and economic points of view. An appendix supplies characteristic data for 'GuD' power stations and an example of a model calculation for a 400 MW e l 'GuD' power station

The major contents in this study are as follows : - long-term forecast to the year of 2040 is provided for nuclear electricity generating capacity by means of logistic curve fitting method. - the role of nuclear power in a national economy is analyzed in terms of environmental regulation. To do so, energy-economy linked model is developed. By using this model, the benefits from the introduction of nuclear power in Korea are estimated. Study on inter-industry economic activity for nuclear industry is carried out by means of an input-output analysis. Nuclear industry is examined in terms of inducement effect of production, of value-added, and of import. - economic analysis of nuclear powergeneration is performed especially taking into consideration wide variations of foreign currency exchange rate. The result is expressed in levelized generating costs. (author). 27 refs., 24 tabs., 44 figs

A demonstration tokamak fusion power plant Demo-CREST is proposed as the device for early realization of net electric powergeneration by fusion energy. The plasma configuration for Demo-CREST is optimized to satisfy the electric breakeven condition (the condition for net electric power, P e net = 0 MW) with the plasma performance of the ITER reference operation mode. This optimization method is considered to be suitable for the design of a demonstration power plant for early realization of net electric powergeneration, because the demonstration power plant has to ensure the net electric generation. Plasma performance should also be more reliably achieved than in past design studies. For the plasma performance planned in the present ITER programme, net electric power from 0 to 500 MW is possible with Demo-CREST under the following engineering conditions: maximum magnetic field 16 T, thermal efficiency 30%, NBI system efficiency 50% and NBI current drive power restricted to 200 MW. By replacing the blanket system with one of higher thermal efficiency, a net electric power of about 1000 MW is also possible so that the performance of the commercial plant with Demo-CREST can also be studied from the economic point of view. The development path from the experimental reactor 'ITER' to the commercial plant 'CREST' through the demonstration power plant 'Demo-CREST' is proposed as an example of the fast track concept. (author)

The utilization of geothermal energy in electrical powergeneration throughout the world is described. Details of generating capacity and cost are given for Larderello, Italy; Wairakei, New Zealand: and the Geysers, USA. In Japan three types of conversion systems are used. These include the direct use of steam, direct use of hot water and binary fluid type systems. The history of Japanese investigation and exploitation of geothermal energy is reviewed and the status of the Matsukawa, Hakone, Otake and Takenoyu geothermal power plants is discussed. It is recommended that laws be enacted in Japan to encourage the development of this form of energy conversion.

The basic physical principles of magnetohydrodynamics and the application of this principle for powergeneration (direct energy conversion) are explained. A magnetohydrodynamic generator (MHDG) is described both in the Faraday and Hall modes. The advantages of the Faraday mode and the Hall mode for different geometries of the generator are mentioned. The conductor used is a fluid - an ionised gas (plasma) or a liquid metal at high temperature. The difficulties in maintaining high temperature and high velocity for the gas and very low temperature at the same time side by side for superconducting magnets to produce a strong magnetic field, are pointed out. The most commonly used gas is purified air. The advantages of MHD generators and the present power crisis have compelled further research in this field in spite of the high costs involved. (A.K.)

The paper reviews and compares experiences and projected future construction and electricity generation costs for nuclear and fossil fired power plants. On the basis of actual operating experience, nuclear power has been demonstrated to be economically competitive with other base load generation options, and international studies project that this economic competitiveness will be largely maintained in the future, over a range of conditions and in a number of countries. However, retaining and improving this competitive position requires concerted efforts to ensure that nuclear plants are constructed within schedule and budgets, and are operated reliably and efficiently. Relevant cost impacting factors is identified, and conclusions for successful nuclear power plant construction and operation are drawn. The desire to attain sustainable development with balanced resource use and control of the environmental and climate impacts of energy systems could lead to renewed interest in nuclear power as an energy source that does not emit greenhouse gases, thus contributing to a revival of the nuclear option. In this regard, mitigation of emissions from fossil-fuelled power plants could lead to restrictions of fossil fuel use and/or result in higher costs of fossil based generation, thus improving the economic competitiveness of nuclear power (au)

A powergeneration system includes a nuclear reactor having a core which in addition to generating heat generates a high frequency electromagnetic radiation. An electromagnetic radiation chamber is positioned to receive at least a portion of the radiation generated by the reactor core. Hydrogen and chlorine are connected into the electromagnetic reactor chamber and react with controlled explosive violence when exposed to the radiation from the nuclear reactor. Oxygen is fed into the reactor chamber as a control medium. The resulting gases under high pressure and temperature are utilized to drive a gas turbine generators. In an alternative embodiment the highly ionized gases, hydrogen and chlorine are utilized as a fluid medium for use in magnetohydrodynamic generators which are attached to the electromagnetic reactor chambers

Full Text Available The proposed paper presents a simple and particularly efficacious MaximumPower Point Tracking (MPPT algorithm based on Silver Mean Method (SMM. This method operates by choosing a search interval from the P-V characteristics of the given solar array and converges to MPP of the Solar Photo-Voltaic (SPV system by shrinking its interval. After achieving the maximumpower, the algorithm stops shrinking and maintains constant voltage until the next interval is decided. The tracking capability efficiency and performance analysis of the proposed algorithm are validated by the simulation and experimental results with a 100W solar panel for variable temperature and irradiance conditions. The results obtained confirm that even without any perturbation and observation process, the proposed method still outperforms the traditional perturb and observe (P&O method by demonstrating far better steady state output, more accuracy and higher efficiency.

The aim of this paper is to improve efficiency of maximumpower point tracking (MPPT) for PV systems. The Support Vector Machine (SVM) was proposed to achieve the MPPT controller. The theoretical, the perturbation and observation (P and O), and incremental conductance (IC) algorithms were used to compare with proposed SVM algorithm. MATLAB models for PV module, theoretical, SVM, P and O, and IC algorithms are implemented. The improved MPPT uses the SVM method to predict the optimum voltage of the PV system in order to extract the maximumpower point (MPP). The SVM technique used two inputs which are solar radiation and ambient temperature of the modeled PV module. The results show that the proposed SVM technique has less Root Mean Square Error (RMSE) and higher efficiency than P and O and IC methods.

This paper presents an overview about the maximum load ability problem and aims to study the main factors that limit this load ability. Specifically this study focuses its attention on determining which electric system buses influence directly on the power demand supply. The proposed approach uses the conventional maximum load ability method modelled by an optimization problem. The solution of this model is performed using the Interior Point methodology. As consequence of this solution method, the Lagrange multipliers are used as parameters that identify the probable 'bottlenecks' in the electric power system. The study also shows the relationship between the Lagrange multipliers and the cost function in the Interior Point optimization interpreted like sensitivity parameters. In order to illustrate the proposed methodology, the approach was applied to an IEEE test system and to assess its performance, a real equivalent electric system from the South- Southeast region of Brazil was simulated. (author)

the platform Arduino with a number of sensors standard can be used as components of an electronic system for acquiring measures and controls. This paper presents the design of a low-cost and effective solar charge controller. This system includes several elements such as the solar panel converter DC/DC, battery, circuit MPPT using Microcontroller, sensors, and the MPPT algorithm. The MPPT (MaximumPower Point Tracker) algorithm has been implemented using an Arduino Nano with the preferred program. The voltage and current of the Panel are taken where the program implemented will work and using this algorithm that MPP will be reached. This paper provides details on the solar charge control device at the maximumpower point. The results include the change of the duty cycle with the change in load and thus mean the variation of the buck converter output voltage and current controlled by the MPPT algorithm.

As competition for the United States power consumer increases, generating companies must seek new ways to do business. One way to keep up with the pace of change is to implement unique ideas into various areas of daily operation at the generating station. From subtle new management styles to ambitious employee education programs, changes in operating the management techniques can produce valuable results over time. An educated confident workforce is capable of vast improvement in efficiency and technical competence. We become empowered

This paper outlines the Life Cycle Management (LCM) program at Ontario PowerGeneration. LCM is carried out at different levels that includes components, systems, unit and fleet. A system involves cumulative effect of individual component aging. These components include steam generators, pressure tubes and feeders. A unit involves an overall unit aging strategy integrating all systems. At the fleet level, there is an optimal strategy for plant-level investments including end-of-life of a unit

Full Text Available The paper presents the functioning of a solar photovoltaic module(PVM that debits direct to on electric battery (EB. By a good adaptingof PVM to EB, so that the no load voltage of the two components (PVMand EB are well suited, during a day the energy value can be reachednear to the maximum possible value, when the PVM functions in themaximum power point (MPP. The proposed solution is much moreeconomic than the classical: PVM + DC – DC + EB because the directcurrent - direct current power converter, is not necessary (DC - DC.

A calculation of the starting torque ratio of permanent magnet, series, and shunt-excited dc motors powered by solar cell arrays is presented for two cases, i.e., with and without a maximum-power-point tracker (MPPT). Defining motor torque magnification by the ratio of the motor torque with an MPPT to the motor torque without an MPPT, a magnification of 3 for the permanent magnet motor and a magnification of 7 for both the series and shunt motors are obtained. The study also shows that all motor types are less sensitive to solar insolation variation in systems including MPPTs as compared to systems without MPPTs.

Assuming the present trend of nuclear powergeneration growth, the ratio of nuclear energy in the world power balance will double by the turn of the century. The time of reasonably exploited uranium resources can be predicted as a few decades. Therefore, new nuclear reactor types and more rational uranium management is needed to prolong life of known uranium resources. It was shown how can a better uranium utilization be expected by closed fuel cycles, and what advantages in uranium management can be expected by a better co-operation between small countries and big powers. (R.P.) 16 refs.; 4 figs

Full Text Available This paper examines the efficiency of a fuzzy logic control (FLC based maximumpower point tracking (MPPT of a photovoltaic (PV system under variable climate conditions and connected load requirements. The PV system including a PV module BP SX150S, buck-boost DC-DC converter, MPPT, and a resistive load is modeled and simulated using Matlab/Simulink package. In order to compare the performance of FLC-based MPPT controller with the conventional perturb and observe (P&O method at different irradiation (G, temperature (T and connected load (RL variations – rising time (tr, recovering time, total average power and MPPT efficiency topics are calculated. The simulation results show that the FLC-based MPPT method can quickly track the maximumpower point (MPP of the PV module at the transient state and effectively eliminates the power oscillation around the MPP of the PV module at steady state, hence more average power can be extracted, in comparison with the conventional P&O method.

We introduce an alternative skew-slash distribution by using the scale mixture of the exponential power distribution. We derive the properties of this distribution and estimate its parameter by Maximum Likelihood and Bayesian methods. By a simulation study we compute the mentioned estimators and their mean square errors, and we provide an example on real data to demonstrate the modeling strength of the new distribution.

Full Text Available We introduce an alternative skew-slash distribution by using the scale mixture of the exponential power distribution. We derive the properties of this distribution and estimate its parameter by Maximum Likelihood and Bayesian methods. By a simulation study we compute the mentioned estimators and their mean square errors, and we provide an example on real data to demonstrate the modeling strength of the new distribution.

We have developed a 150-W SiC-based photovoltaic (PV)-inverter with the maximumpower point tracking (MPPT) function. The newly developed inverter achieved a state-of-the-art combination of the weight (0.79 kg) and the volume (790 mm3) as a 150-250 W class PV-inverter. As compared to the original version that we have previously reported, the weight and volume were decreased by 37% and 38%, respectively. This compactness originated from the optimized circuit structure and the increased density of a wiring circuit. Conversion efficiencies of the MPPT charge controller and the direct current (DC)-alternating current (AC) converter reached 96.4% and 87.6%, respectively. These efficiency values are comparable to those for the original version. We have developed a PV powergeneration system consisting of this inverter, a spherical Si solar cell module, and a 15-V Li-ion laminated battery. The total weight of the system was below 6 kg. The developed system exhibited stable output power characteristics, even when the weather conditions were fluctuated. These compactness, high efficiencies, and excellent stability clearly indicated the feasibility of SiC power devices even for sub-kW class PV powergeneration systems.

Utilizing the adjoint equations that originate from the calculus of variations, we have calculated the maximum thermal efficiency that is theoretically attainable by free-piston engine generators considering the work loss due to friction and Joule heat. Based on the adjoint equations with seven dimensionless parameters, the trajectory of the piston, the histories of the electric current, the work done, and the two kinds of losses have been derived in analytic forms. Using these we have conducted parametric studies for the optimized Otto and Brayton cycles. The smallness of the pressure ratio of the Brayton cycle makes the net work done negative even when the duration of heat addition is optimized to give the maximum amount of heat addition. For the Otto cycle, the net work done is positive, and both types of losses relative to the gross work done become smaller with the larger compression ratio. Another remarkable feature of the optimized Brayton cycle is that the piston trajectory of the heat addition/disposal process is expressed by the same equation as that of an adiabatic process. The maximum thermal efficiency of any combination of isochoric and isobaric heat addition/disposal processes, such as the Sabathe cycle, may be deduced by applying the methods described here.

Research was conducted to develop an electrostatic powergenerator for future lunar missions that facilitate the utilization of lunar resources. The lunar surface is known to be negatively charged from the constant bombardment of electrons and protons from the solar wind. The resulting negative electrostatic charge on the dust particles, in the lunar vacuum, causes them to repel each other minimizing the potential. The result is a layer of suspended dust about one meter above the lunar surface. This phenomenon was observed by both Clementine and Surveyor spacecrafts. During the Apollo 17 lunar landing, the charged dust was a major hindrance, as it was attracted to the astronauts' spacesuits, equipment, and the lunar buggies. The dust accumulated on the spacesuits caused reduced visibility for the astronauts, and was unavoidably transported inside the spacecraft where it caused breathing irritation [1]. In the lunar vacuum, the maximum charge on the particles can be extremely high. An article in the journal "Nature", titled "Moon too static for astronauts?" (Feb 2, 2007) estimates that the lunar surface is charged with up to several thousand volts [2]. The electrostatic powergenerator was devised to alleviate the hazardous effects of negatively charged lunar soil by neutralizing the charged particles through capacitive coupling and thereby simultaneously harnessing power through electric charging [3]. The amount of powergenerated or collected is dependent on the areal coverage of the device and hovering speed over the lunar soil surface. A thin-film array of capacitors can be continuously charged and sequentially discharged using a time-differentiated trigger discharge process to produce a pulse train of discharge for DC mode output. By controlling the pulse interval, the DC mode power can be modulated for powering devices and equipment. In conjunction with a power storage system, the electrostatic powergenerator can be a power source for a lunar rover or other

Full Text Available A photovoltaic pulse charger (PV-PC using high-frequency pulse train for charging lead-acid battery (LAB is proposed not only to explore the charging behavior with maximumpower point tracking (MPPT but also to delay sulfating crystallization on the electrode pores of the LAB to prolong the battery life, which is achieved due to a brief pulse break between adjacent pulses that refreshes the discharging of LAB. Maximum energy transfer between the PV module and a boost current converter (BCC is modeled to maximize the charging energy for LAB under different solar insolation. A duty control, guided by a power-increment-aided incremental-conductance MPPT (PI-INC MPPT, is implemented to the BCC that operates at maximumpower point (MPP against the random insolation. A 250 W PV-PC system for charging a four-in-series LAB (48 Vdc is examined. The charging behavior of the PV-PC system in comparison with that of CC-CV charger is studied. Four scenarios of charging statuses of PV-BC system under different solar insolation changes are investigated and compared with that using INC MPPT.

This paper presents a complete design of a two-level control system to capture maximumpower in wind energy conversion systems. The upper level of the proposed control system adopts a modified line search optimization algorithm to determine a setpoint for the wind turbine speed. The calculated speed setpoint corresponds to the maximumpower point at given operating conditions. The speed setpoint is fed to a generalized predictive controller at the lower level of the control system. A different formulation, that treats the aerodynamic torque as a disturbance, is postulated to derive the control law. The objective is to accurately track the setpoint while keeping the control action free from unacceptably fast or frequent variations. Simulation results based on a realistic model of a 1.5 MW wind turbine confirm the superiority of the proposed control scheme to the conventional ones. - Highlights: • The structure of a MPPT (maximumpower point tracking) scheme is presented. • The scheme is divided into the optimization algorithm and the tracking controller. • The optimization algorithm is based on an online line search numerical algorithm. • The tracking controller is treating the aerodynamics torque as a loop disturbance. • The control technique is simulated with stochastic wind speed by Simulink and FAST

In this paper the simulation model of an artificial neural network (ANN) based maximumpower point tracking controller has been developed. The controller consists of an ANN tracker and the optimal control unit. The ANN tracker estimates the voltages and currents corresponding to a maximumpower delivered by solar PV (photovoltaic) array for variable cell temperature and solar radiation. The cell temperature is considered as a function of ambient air temperature, wind speed and solar radiation. The tracker is trained employing a set of 124 patterns using the back propagation algorithm. The mean square error of tracker output and target values is set to be of the order of 10{sup -5} and the successful convergent of learning process takes 1281 epochs. The accuracy of the ANN tracker has been validated by employing different test data sets. The control unit uses the estimates of the ANN tracker to adjust the duty cycle of the chopper to optimum value needed for maximumpower transfer to the specified load. (author)

Wind energy is currently the fastest growing type of renewable energy. The main motivation is led by more strict emission constraints and higher fuel prices. In addition, recent developments in wind turbine technology and financial incentives have made wind energy technically and economically viable almost anywhere. In restructured power systems, reliable and economical operation of power systems are the two main objectives for the ISO. The ability to control the output of wind turbines is limited and the capacity of a wind farm changes according to wind speeds. Since this type of generation has no production costs, all production is taken by the system. Although, insufficient operational planning of power systems considering wind generation could result in higher system operation costs and off-peak transmission congestions. In addition, a GENCO can participate in short-term power markets in restructured power systems. The goal of a GENCO is to sell energy in such a way that would maximize its profitability. However, due to market price fluctuations and wind forecasting errors, it is essential for the wind GENCO to keep its financial risk at an acceptable level when constituting market bidding strategies. This dissertation discusses assumptions, functions, and methodologies that optimize short-term operations of power systems considering wind energy, and that optimize bidding strategies for wind producers in short-term markets. This dissertation also discusses uncertainties associated with electricity market environment and wind power forecasting that can expose market participants to a significant risk level when managing the tradeoff between profitability and risk.

Energy efficiency is the cheapest source of energy that has escaped the minds of the politicians in the developing countries. This paper argues for large scale utility led end use efficiency programs in a new paradigm, where 1 million efficient light bulbs is synonymous to a 50 MW power station that costs only 2% of the traditional fossil fuel power station and zero maintenance. Bulk procurement, setting up new standards and generation of certified emissions reduction is part of this strategy. It discusses implementation of a $20 million pilot in the Philippines supported by the Asian Development Bank.

Full Text Available The purpose of this study was to investigate the effects of plyometric and cluster resistance training on explosive power and maximum strength in karate players. Eighteen women, karate players (age mean ± SD 18.22 ± 3.02 years, mean height 163 ± 0.63cm, and mean body mass 53.25 ± 7.34 kg were selected as volunteer samples. They were divided into two groups with respect to their recorded one repetition maximum squat exercise: [1] plyometric training (PT=9 and [2] Cluster training (CT=9 groups and performed a 9-week resistance training protocol that included three stages; [1] General fitness (2 weeks, [2] Strength (4 weeks and [3] Power (3 weeks. Each group performed strength and power trainings for 7 weeks in stage two and three with owned protocol. The subjects were evaluated three times before stage one and after two and three stages for maximum strength and power. Data was analyzed using two way Repeated Measures (ANOVA at a significance level of (P≤0.05. The statistical analysis showed that training stages on all research variables had a significant impact. The maximum strength of the pre-test, post-test strength and post-test power were in cluster group: 29.05 ± 1.54; 32.89 ± 2.80 and 48.74 ± 4.33w and in plyometric group were 26.98 ± 1.54; 38.48 ± 2.80 and 49.82 ± 4.33w respectively. The explosive power of the pre-test, post-test strength and post-test power in cluster group were 359.32±36.20; 427.91±34.56 and 460.55±36.80w and in plyometric group were 333.90±36.20; 400.33±34.56 and 465.20±36.80w respectively. However, there were not statistically significant differences in research variables between resistance cluster and plyometric training groups after 7 weeks. The results indicated both cluster and plyometric training program seems to improve physical fitness elements at the same levels.

By principle, hydroelectric powergeneration relies on the law of conservation of energy where kinetic energy that resulted from the movement of the mass of water from the river is translated into electr icity, the quantum of which depends on systemic variables viz: plant efficiency, volumetric water flow through the turbine and ...

This document from OECD deals with the choices between the different means of producing electricity: supply and demand trends, powergeneration choices, management of development and technologies, environmental impacts and costs around energy sources. Separate abstracts were prepared for all the papers of this volume. (TEC)

A method is described for powergeneration from a recirculating superheat-reheat circuit with multiple expansion stages which alleviates complex control systems and minimizes thermal cycling of system components, particularly the reheater. The invention includes preheating cold reheat fluid from the first expansion stage prior to its entering the reheater with fluid from the evaporator or drum component

An existent magnetic field generation device for magnetohydrodynamic electric powergeneration comprises at least a pair of permanent magnets disposed to an inner circumferential surface of a yoke having such a cross sectional area that two pairs of parallel sides are present, in which different magnetic poles are opposed while interposing a flow channel for a conductive fluid therebetween. Then, first permanent magnets which generate main magnetic fields are disposed each at a gap sandwiching a plane surface including a center axis of a flow channel for the conductive fluid. Second permanent magnets which generate auxiliary magnetic fields are disposed to an inner circumferential surface of a yoke intersecting the yoke to which the first permanent magnets are disposed. The magnetic poles on the side of the flow channel for the second permanent magnets have identical polarity with that of the magnetic poles of the adjacent first permanent magnets. As a result, a magnetic flux density in the flow channel for the conductive fluid can be kept homogeneous and at a high level from a position of the axial line of the flow channel to the outer circumference, thereby enabling to remarkably improve a powergeneration efficiency. (N.H.)

Full Text Available Generatingpower is of great importance nowadays across the world. However, recently, the world became aware of the climatic changes due to the greenhouse effect caused by CO2 emissions and began seeking solutions to reduce the negative impact on the environment. Besides, the exhaustion of fossil fuels and their environmental impact, make it is crucial to develop clean energy sources, and efforts are focused on developing and improving the efficiency of all energy consuming systems. The tubular permanent magnet linear generators (TPMLGs are the best candidate for energy converters. Despite being suffering problem of attraction force between permanent magnets and stator teeth, to eliminate such attraction force, ironless-stator could be considered. Thus, they could waive the presence of any magnetic attraction between the moving and stator part. This paper presents the design and analysis of ironless -cored TPMLG for low grid powergeneration. The main advantages of this generator are the low cogging force and high efficiency. Therefore, the magnetic field computation of the proposed generator has been performed by applying a magnetic vector potential and utilizing a 2-D finite element analysis (FEA. Moreover, the experimental results for the current profile, pressure profile and velocity profile have been presented.

The Ocean PowerGenerator is both technically and economically suitable for deployment in the Gulf Stream from the US Navy facility in Dania, Florida. Yet to be completed is the calibration test in the Chesapeake Bay with the prototype dual hydroturbine Underwater Electric Kite. For the production units a revised design includes two ballast tanks mounted as pontoons to provide buoyancy and depth control. The power rating of the Ocean PowerGenerator has been doubled to 200 kW ready for insertion into the utility grid. The projected cost for a 10 MW installation is $3.38 per watt, a cost that is consistent with wind power pricing when it was in its deployment infancy, and a cost that is far better than photovoltaics after 25 years of research and development. The Gulf Stream flows 24 hours per day, and water flow is both environmentally and ecologically perfect as a renewable energy source. No real estate purchases are necessary, and you cannot see, hear, smell, or touch an Ocean PowerGenerator.

An energy security index was developed to measure how the introduction of nuclear powergeneration improved the national security of energy supply in Korea. Using the developed index, a quantitative effort was made to analyze the relationship between the nuclear powergeneration and the national energy security. Environmental impacts were evaluated and a simplified external cost of a specific coal-fired power plant in Korea was estimated using the QUERI program, which was developed by IAEA. In doing so, efforts were made to quantify the health impacts such as mortality, morbidity, and respiratory hospital admissions due to particulates, SOx, and Nox. The effects of CO 2 emission regulation on the national economy were evaluated. In doing so, the introduction of carbon tax was assumed. Several scenarios were established about the share of nuclear powergeneration and an effort was made to see how much contribution nuclear energy could make to lessen the burden of the regulation on the national economy. This study re-evaluated the methods for estimating and distributing decommissioning cost of nuclear power plant over lifetime. It was resulted out that the annual decommissioning deposit and consequently, the annual decommissioning cost could vary significantly depending on estimating and distributing methods. (author). 24 refs., 44 tabs., 9 figs

This paper deals wind energy based powergeneration system using Permanent Magnet Synchronous Generator (PMSG). It is controlled using advanced enhanced phase-lock loop for power quality features using distribution static compensator to eliminate the harmonics and to provide KVAR compensation as well as load balancing. It also manages rated potential at the point of common interface under linear and non-linear loads. In order to have better efficiency and reliable operation of PMSG driven by wind turbine, it is necessary to analyze the governing equation of wind based turbine and PMSG under fixed and variable wind speed. For handling power quality problems, power electronics based shunt connected custom power device is used in three wire system. The simulations in MATLAB/Simulink environment have been carried out in order to demonstrate this model and control approach used for the power quality enhancement. The performance results show the adequate performance of PMSG based powergeneration system and control algorithm.

This paper presents a simple and low-cost method to capture maximumpower throughput of permanent magnet brushless DC (BLDC) generator. Conventional methods of rectification are based on passive converters, and because the current waveform cannot be controlled as ideal waveform, a highly distorted current is drawn from brushless generator. It leads to lower power factor and reduces the efficiency and power per ampere capability. So, in this study an active six-witch power converter is employe...

iii Approved for public release; distribution is unlimited MICROGRID CONTROL STRATEGY UTLIZING THERMAL ENERGY STORAGE WITH RENEWABLE SOLAR AND WIND... control tracks increasing powergeneration in the morning. The batteries require a large amount of electrical power to charge every morning, as charge ...is 37 lost throughout the night. This causes the solar panels to output their maximumpowergeneration. The MPPT control records when power

A computational model has been developed in order to simulate the thermal and electric behavior of thermoelectric generators. This model solves the nonlinear system of equations of the thermoelectric and heat transfer equations. The inputs of the program are the thermoelectric parameters as a function of temperature and the boundary conditions, (room temperature and residual heat flux). The outputs are the temperature values of all the elements forming the thermoelectric generator, (performance, electric power, voltage and electric current generated). The model solves the equation system using the finite difference method and semi-empirical expressions for the convection coefficients. A thermoelectric electric powergeneration test bench has been built in order to validate and determine the accuracy of the computational model, which maximum error is lower than 5%. The objective of this study is to create a design tool that allows us to solve the system of equations involved in the electric generation process without needing to impose boundary conditions that are not known in the design phase, such as the temperature of the Peltier modules. With the computational model, we study the influence of the heat flux supplied as well as the room temperature on the electric powergenerated.

Full Text Available Ocean wave energy plays a significant role in meeting the growing demand of electric power. Economic, environmental, and technical advantages of wave energy set it apart from other renewable energy resources. Present study describes a newly proposed Mechanical Wave Energy Converter (MEWC that is employed to harness heave motion of floating buoy to generatepower. Focus is on the conceptual development of the device, illustrating details of component level analysis. Employed methodology has many advantages such as i simple and easy fabrication; ii easy to control the operations during rough weather; and iii low failure rate during normal sea conditions. Experimental investigations carried out on the scaled model of MWEC show better performance and its capability to generatepower at higher efficiency in regular wave fields. Design Failure Mode and Effect Analysis (FMEA shows rare failure rates for all components except the floating buoy.

"This book offers an analytical overview of established electric generation processes, along with the present status & improvements for meeting the strains of reconstruction. These old methods are hydro-electric, thermal & nuclear power production. The book covers climatic constraints; their affects and how they are shaping thermal production. The book also covers the main renewable energy sources, wind and PV cells and the hybrids arising out of these. It covers distributed generation which already has a large presence is now being joined by wind & PV energies. It covers their accommodation in the present system. It introduces energy stores for electricity; when they burst upon the scene in full strength are expected to revolutionize electricity production. In all the subjects covered, there are references to power marketing & how it is shaping production. There will also be a reference chapter on how the power market works"--Provided by publisher.

An optical technique for high-power radio-frequency (RF) signal generation is described. The technique uses a unique photodetector based on a traveling-wave design driven by an appropriately modulated light source. The traveling-wave photodetector (TWPD) exhibits simultaneously a theoretical quantum efficiency approaching 100 % and a very large electrical bandwidth. Additionally, it is capable of dissipating the high-power levels required for the RF generation technique. The modulated light source is formed by either the beating together of two lasers or by the direct modulation of a light source. A system example is given which predicts RF power levels of 100's of mW's at millimeter wave frequencies with a theoretical ''wall-plug'' efficiency approaching 34%

A systematic managed process for steam generators has been implemented at Ontario PowerGeneration (OPG) nuclear stations for the past several years. One of the key requirements of this managed process is to have in place long range Steam Generator Life Cycle Management (SG LCM) plans for each unit. The primary goal of these plans is to maximize the value of the nuclear facility through safe and reliable steam generator operation over the expected life of the units. The SG LCM plans integrate and schedule all steam generator actions such as inspection, operation, maintenance, modifications, repairs, assessments, R and D, performance monitoring and feedback. This paper discusses OPG steam generator life cycle management experience to date, including successes, failures and how lessons learned have been re-applied. The discussion includes relevant examples from each of the operating stations: Pickering B and Darlington. It also includes some of the experience and lessons learned from the activities carried out to refurbish the steam generators at Pickering A after several years in long term lay-up. The paper is structured along the various degradation modes that have been observed to date at these sites, including monitoring and mitigating actions taken and future plans. (author)

Full Text Available The maximumpower point tracking (MPPT of photovoltaic systems must be as fast and accurate as possible to increase the power production, which eventually increases the PV system profitability. This paper proposes and mathematically analyses a sliding-mode controller to provide a fast and accurate maximumpower point tracking in grid-connected photovoltaic systems using a single control stage. This approach avoids the circular dependency in the design of classical cascade controllers used to optimize the photovoltaic system operation, and at the same time, it reduces the number of controllers and avoids the use of linearized models to provide global stability in all the operation range. Such a compact solution also reduces the system cost and implementation complexity. To ensure the stability of the proposed solution, detailed mathematical analyses are performed to demonstrate the fulfillment of the transversality, reachability and equivalent control conditions. Finally, the performance of the proposed solution is validated using detailed simulations, executed in the power electronics simulator PSIM, accounting for both environmental and load perturbations.

The reactor concept analyzed is a 233 UF 6 core surrounded by a molten salt (Li 7 F, BeF 2 , ThF 4 ) blanket. Nuclear survey calculations were carried out for both spherical and cylindrical geometries. A maximum breeding ratio of 1.22 was found. Thermodynamic cycle calculations were performed for a variety of Rankine cycles. Optimization of a Rankine cycle for a gas core breeder reactor employing an intermediate heat exchanger gave a maximum efficiency of 37 percent. A conceptual design is presented along with a system layout for a 1000 MW stationary power plant. The advantages of the GCBR are as follows: (1) high efficiency, (2) simplified on-line reprocessing, (3) inherent safety considerations, (4) high breeding ratio, (5) possibility of burning all or most of the long-lived nuclear waste actinides, and (6) possibility of extrapolating the technology to higher temperatures and MHD direct conversion

Full Text Available Solar energy is one form of the renewable energy which is very abundant in regions close to the equator. One application of solar energy is for street light. This research focuses on using the maximumpower point tracking technique (MPPT, particularly the perturb and observe (P&O algorithm, to charge battery for street light system. The proposed charger circuit can achieve 20.73% higher power efficiency compared to that of non-MPPT charger. We also develop the LED driver circuit for the system which can achieve power efficiency up to 91.9% at a current of 1.06 A. The proposed street lightning system can be implemented with a relatively low cost for public areas.

This article deals with the possibility of using alternative energy sources for power of biomedical sensors with low power consumption, especially using the Peltier effect sources. Energy for powering of the target device has been used from the available renewable photovoltaic effect. The work is using of "energy harvesting" or "harvest energy" produced by autonomous generator harvesting accumulate energy. It allows to start working from 0.25 V. Measuring chain consists of further circuit which is a digital monitoring device for monitoring a voltage, current and power with I2C bus interface. Using the Peltier effect was first tested in a thermocontainer with water when the water heating occurred on the basis of different temperature differential between the cold and hot side of the Peltier element result in the production of energy. Realized prototype was also experimentally tested on human skin, specifically on the back, both in idle mode and under load.

This paper addresses how Distributed Generation (DG), particularly when configured in Combined Heat and Power (CHP) mode, can become a powerful reliability solution in highlight automated factories, especially when integrated with complimentary Power Quality (PQ) measures. The paper presents results from the PQ audit conducted at a highly automated plant over last year. It was found that the main problems for the equipment installed were voltage sags. Among all categories of electrical disturbances, the voltage sag (dip) and momentary interruption are the nemeses of the automated industrial process. The paper analyzes the capabilities of modern electronic power supplies and the convenience of embedded solution. Finally it is addressed the role of the DG/CHP on the reliability of digital factories. (author)

{open_quotes}Distributed Generation{close_quotes} has become the {open_quotes}buzz{close_quotes} word of an electric utility industry facing deregulation. Many industrial facilities utilize equipment in distributed installations to serve the needs of a thermal host through the capture of exhaust energy in a heat recovery steam generator. The electrical powergenerated is then sold as a {open_quotes}side benefit{close_quotes} to the cost-effective supply of high quality thermal energy. Distributed generation is desirable for many different reasons, each with unique characteristics of the product. Many years of experience in the distributed generation market has helped Stewart & Stevenson to define a range of product features that are crucial to most any application. The following paper will highlight a few of these applications. The paper will also examine the range of products currently available and in development. Finally, we will survey the additional services offered by Stewart & Stevenson to meet the needs of a rapidly changing powergeneration industry.

In this paper, we propose to perform a numerical technique based on genetic algorithms (GAs) to identify the electrical parameters (I{sub s}, I{sub ph}, R{sub s}, R{sub sh}, and n) of photovoltaic (PV) solar cells and modules. These parameters were used to determine the corresponding maximumpower point (MPP) from the illuminated current-voltage (I-V) characteristic. The one diode type approach is used to model the AM1.5 I-V characteristic of the solar cell. To extract electrical parameters, the approach is formulated as a non convex optimization problem. The GAs approach was used as a numerical technique in order to overcome problems involved in the local minima in the case of non convex optimization criteria. Compared to other methods, we find that the GAs is a very efficient technique to estimate the electrical parameters of PV solar cells and modules. Indeed, the race of the algorithm stopped after five generations in the case of PV solar cells and seven generations in the case of PV modules. The identified parameters are then used to extract the maximumpower working points for both cell and module. (author)

An electric power supply, small enough to be man-portable, is being developed for remote, terrestrial applications. This system is designed for an operating lifetime of five years without maintenance or refueling. A small Radioisotope Stirling Generator (RSG) has been developed. The energy source of the generator is a 60 watt plutonium-238 fuel clad used in the General Purpose Heat Sources (GPHS) developed for space applications. A free piston Stirling Engine drives a linear alternator to convert the heat to power. The system weighs about 7.5 kg and produces 11 watts AC power with a conversion efficiency of 18.5%. Two engine models have been designed, fabricated, and tested to date: (a) a developmental model instrumented to confirm and test parameters, and (b) an electrically heated model with an electrical heater equipped power input leads. Critical components have been tested for 10,000 to 20,000 hours. One complete generator has been operating for over 11,000 hours. Radioisotope heated prototypes are expected to be fabricated and tested in late 1995

The workshop that was held in Madrid 25-27 May 1994 included participation by experts from 16 countries. They represented such diverse fields and disciplines as technology, governmental regulation, economics, and environment. Thus, the participants provided an excellent cross section of key areas and a diversity of viewpoints. At the workshop, a broad range of topics regarding gas-fired electric powergeneration was discussed. These included political, regulatory and financial issues as well as more specific technical questions regarding the environment, energy efficiency, advanced generation technologies and the status of competitive developments. Important technological advances in gas-based power and CHP technologies have already been achieved including higher energy efficiency and lower emissions, with further improvements expected in the near future. Advanced technology trends include: (a) The use of gas technology to reduce emissions from existing coal-fired power plants. (b) The wide-spread application of combined-cycle gas turbines in new power plants and the growing use of aero-derivative gas turbines in CHP applications. (c) Phosphoric acid fuel cells that are being introduced commercially. Their market penetration will grow over the next 10 years. The next generation of fuel cells (solid oxide and molten carbonate) is expected to enter the market around the year 2000. (EG)

Full Text Available An extremum seeking control (ESC scheme is proposed for maximumpower point tracking (MPPT in photovoltaic powergeneration systems. The robustness of the proposed scheme toward irradiance changes is enhanced by implementing the ESC scheme using a sliding mode control (SMC law. In the proposed approach, the chattering phenomenon caused by high frequency switching is suppressed by means of a sliding layer concept. Moreover, in implementing the proposed controller, the optimal value of the gain constant is determined using a particle swarm optimization (PSO algorithm. The experimental and simulation results show that the proposed PSO-based sliding mode ESC (SMESC control scheme yields a better transient response, steady-state stability, and robustness than traditional MPPT schemes based on gradient detection methods.

A robust maximumpower point tracker (MPPT) using sliding mode controller for the three-phase grid-connected photovoltaic system has been proposed in this paper. Contrary to the previous controller, the proposed system consists of MPPT controller and current controller for tight regulation of the current. The proposed MPPT controller generates current reference directly from the solar array power information and the current controller uses the integral sliding mode for the tight control of current. The proposed system can prevent the current overshoot and provide optimal design for the system components. The structure of the proposed system is simple, and it shows robust tracking property against modeling uncertainties and parameter variations. Mathematical modeling is developed and the experimental results verify the validity of the proposed controller. (author)

The part of generating units within the power system is more than providing power and energy. Their performance are not only measured by their energy efficiency and availability. Namely, there is a strong interaction between the generating units and the power system. The units are essential components of the system: for a given load profile the frequency variation follows directly from the behaviour of the units and their ability to adapt their power output. In the same way, the voltage at the units terminals are the key points to which the voltage profile at each node of the network is linked through the active and especially the reactive power flows. Therefore, the customer will experience the frequency and voltage variations induced by the units behaviour. Moreover, in case of adverse conditions, if the units do not operate as well as expected or trip, a portion of the system, may be the whole system, may collapse. The limitation of the performance of a unit has two kinds of consequences. Firstly, it may result in an increased amount of not supplied energy or loss of load probability: for example if the primary reserve is not sufficient, a generator tripping may lead to an abnormal frequency deviation, and load may have to be shed to restore the balance. Secondly, the limitation of a unit performance results in an economic over-cost for the system: for instance, if not enough `cheap` units are able to load-following, other units with higher operating costs have to be started up. We would like to stress the interest for the operators and design teams of the units on the one hand, and the operators and design teams of the system on the other hand, of dialog and information exchange, in operation but also at the conception stage, in order to find a satisfactory compromise between the system requirements and the consequences for the generating units. (authors). 11 refs., 4 figs.

Most of the world's geothermal power plants have been built in 1970s and 1980s following 1973 oil crisis. Urgency to generate electricity from alternative energy sources and the fact that geothermal energy was essentially free adversely affected careful designs of plants which would maximize their performance for a given geothermal resource. There are, however, tremendous potentials to improve performance of many existing geothermal power plants by retrofitting, optimizing the operating conditions, re-selecting the most appropriate binary fluid in binary plants, and considering cogeneration such as a district heating and/or cooling system or a system to preheat water entering boilers in industrial facilities. In this dissertation, some representative geothermal resources and existing geothermal power plants in Nevada are investigated to show these potentials. Economic analysis of a typical geothermal resource shows that geothermal heating and cooling may generate up to 3 times as much revenue as powergeneration alone. A district heating/cooling system is designed for its incorporation into an existing 27 MW air-cooled binary geothermal power plant. The system as designed has the capability to meet the entire heating needs of an industrial park as well as 40% of its cooling needs, generating potential revenues of $14,040,000 per year. A study of the power plant shows that evaporative cooling can increase the power output by up to 29% in summer by decreasing the condenser temperature. The power output of the plant can be increased by 2.8 percent by optimizing the maximum pressure in the cycle. Also, replacing the existing working fluid isobutane by butane, R-114, isopentane, and pentane can increase the power output by up to 2.5 percent. Investigation of some well-known geothermal powergeneration technologies as alternatives to an existing 12.8 MW single-flash geothermal power plant shows that double-flash, binary, and combined flash/binary designs can increase the

Energy supply and climate change are nowadays two of the most outstanding problems which societies have to cope with under a context of increasing energy needs. Public awareness of these problems is driving political willingness to take actions for tackling them in a swift and efficient manner. Such actions mainly focus in increasing energy efficiency, in decreasing dependence on fossil fuels, and in reducing greenhouse gas emissions. In this context, power systems are undergoing important changes in the way they are planned and managed. On the one hand, vertically integrated structures are being replaced by market structures in which power systems are un-bundled. On the other, power systems that once relied on large powergeneration facilities are witnessing the end of these facilities' life-cycle and, consequently, their decommissioning. The role of distributed energy resources such as wind and solar powergenerators is becoming increasingly important in this context. However, the large-scale integration of such type of generation presents many challenges due, for instance, to the uncertainty associated to the variability of their production. Nevertheless, advanced forecasting tools may be combined with more controllable elements such as energy storage devices, gas turbines, and controllable loads to form systems that aim to reduce the impacts that may be caused by these uncertainties. This thesis addresses the management under market conditions of these types of systems that act like independent societies and which are herewith named power system cells. From the available literature, a unified view of power system scheduling problems is also proposed as a first step for managing sets of power system cells in a multi-cell management framework. Then, methodologies for performing the optimal day-ahead scheduling of single power system cells are proposed, discussed and evaluated under both a deterministic and a stochastic framework that directly integrates the

Although electrokinetic effects are not new, only recently have they been investigated for possible use in energy conversion devices. We have recently reported the electrokinetic generation of molecular hydrogen from rapidly flowing liquid water microjets [Duffin et al. JPCC 2007, 111, 12031]. Here, we describe the use of liquid water microjets for direct conversion of electrokinetic energy to electrical power. Previous studies of electrokinetic power production have reported low efficiencies ({approx}3%), limited by back conduction of ions at the surface and in the bulk liquid. Liquid microjets eliminate energy dissipation due to back conduction and, measuring only at the jet target, yield conversion efficiencies exceeding 10%.

the challenging issues and, more importantly, to leverage the energy generation, stringent demands from both utility operators and consumers have been imposed on the DPGS. Furthermore, as the core of energy conversion, numerous power electronic converters employing advanced control techniques have been developed...... for the DPGS to consolidate the integration. In light of the above, this paper reviews the power-conversion and control technologies used for DPGSs. The impacts of the DPGS on the distributed grid are also examined, and more importantly, strategies for enhancing the connection and protection of the DPGS...

Full Text Available Mismatching effects due to partial shaded conditions are the major drawbacks existing in today’s photovoltaic (PV systems. These mismatch effects are greatly reduced in distributed PV system architecture where each panel is effectively decoupled from its neighboring panel. To obtain the optimal operation of the PV panels, maximumpower point tracking (MPPT techniques are used. In partial shaded conditions, detecting the maximum operating point is difficult as the characteristic curves are complex with multiple peaks. In this paper, a neural network control technique is employed for MPPT. Detailed analyses were carried out on MPPT controllers in centralized and distributed architecture under partial shaded environments. The efficiency of the MPPT controllers and the effectiveness of the proposed control technique under partial shaded environments was examined using MATLAB software. The results were validated through experimentation.

Although the power clean test is routinely used to assess strength and power performance in adult athletes, the reliability of this measure in younger populations has not been examined. Therefore, the purpose of this study was to determine the reliability of the one repetition maximum (1 RM) power clean in adolescent athletes. Thirty-six male athletes (age 15.9 ± 1.1 yrs, body mass 79.1 ± 20.3 kg, height 175.1 ±7.4 cm) who had more than 1 year of training experience with weightlifting exercises performed a 1 RM power clean on two nonconsecutive days in the afternoon following standardized procedures. All test procedures were supervised by a senior level weightlifting coach and consisted of a systematic progression in test load until the maximum resistance that could be lifted for one repetition using proper exercise technique was determined. Data were analyzed using an intraclass correlation coefficient (ICC [2,k]), Pearson correlation coefficient (r), repeated measures ANOVA, Bland-Altman plot, and typical error analyses. Analysis of the data revealed that the test measures were highly reliable demonstrating a test-retest ICC of 0.98 (95% CI = 0.96–0.99). Testing also demonstrated a strong relationship between 1 RM measures on trial 1 and trial 2 (r=0.98, pinjuries occurred during the study period and the testing protocol was well-tolerated by all subjects. These findings indicate that 1 RM power clean testing has a high degree of reproducibility in trained male adolescent athletes when standardized testing procedures are followed and qualified instruction is present. PMID:22233786

Full Text Available In modern wind farms, maximumpower point tracking (MPPT is widely implemented. Using the MPPT method, each individual wind turbine is controlled by its pitch angle and tip speed ratio to generate the maximum active power. In a wind farm, the upstream wind turbine may cause power loss to its downstream wind turbines due to the wake effect. According to the wake model, downstream power loss is also determined by the pitch angle and tip speed ratio of the upstream wind turbine. By optimizing the pitch angle and tip speed ratio of each wind turbine, the total active power of the wind farm can be increased. In this paper, the optimal pitch angle and tip speed ratio are selected for each wind turbine by the exhausted search. Considering the estimation error of the wake model, a solution to implement the optimized pitch angle and tip speed ratio is proposed, which is to generate the optimal control curves for each individual wind turbine off-line. In typical wind farms with regular layout, based on the detailed analysis of the influence of pitch angle and tip speed ratio on the total active power of the wind farm by the exhausted search, the optimization is simplified with the reduced computation complexity. By using the optimized control curves, the annual energy production (AEP is increased by 1.03% compared to using the MPPT method in a case-study of a typical eighty-turbine wind farm.

Recently, a triboelectric generator (TEG) has been invented to convert mechanical energy into electricity by a conjunction of triboelectrification and electrostatic induction. Compared to the traditional electromagnetic generator (EMG) that produces a high output current but low voltage, the TEG has different output characteristics of low output current but high output voltage. In this paper, we present a comparative study regarding the fundamentals of TEGs and EMGs. The power output performances of the EMG and the TEG have a special complementary relationship, with the EMG being a voltage source and the TEG a current source. Utilizing a power transformed and managed (PTM) system, the current output of a TEG can reach as high as ∼3 mA, which can be coupled with the output signal of an EMG to enhance the output power. We also demonstrate a design to integrate a TEG and an EMG into a single device for simultaneously harvesting mechanical energy. In addition, the integrated NGs can independently output a high voltage and a high current to meet special needs.

In order to increase production of an EAF (electric arc furnace) by reduction of melting time, one can increase transferred power to the EAF. In other words a certain value of energy can be transferred to the EAF in less time. The transferred power to the EAF reduces when series reactors are utilized in order to have stable arc with desired characteristics. To compensate the reduced transferred power, the secondary voltage of the EAF transformer should be increased by tap changing of the transformer. On the other hand, after any tap changing of the EAF transformer, improved arc stability is degraded. Therefore, the series reactor and EAF transformer tap changing should be simultaneously determined to achieve arc with desired characteristics. In this research, three approaches are proposed to calculate the EAF system parameters, by which the optimal set-points of the different series reactor and EAF transformer taps are determined. The electric characteristics relevant to the EAF for the all transformer and series reactor taps with and without SVC (static VAr compensator) are plotted and based on these graphs the optimal set-points are tabulated. Finally, an economic evaluation is also presented for the methods. - Highlights: • The main goal is to transfer the maximumpower to electric arc furnace. • Optimal transformer and series reactor taps are determined. • Arc stability and transferred power to EAF determine the optimal performance. • An economic assessment is done and the number of increased meltings is calculated

The world-wide move to deregulation of the electricity and other energy markets, concerns about the environment, and advances in renewable and high efficiency technologies has led to major emphasis being placed on the use of small powergeneration units in a variety of forms. The paper reviews the position of distributed generation (DG, as these small units are called in comparison with central power plants) with respect to the installation and interconnection of such units with the classical grid infrastructure. In particular, the status of technical standards both in Europe and USA, possible ways to improve the interconnection situation, and also the need for decisions that provide a satisfactory position for the network operator (who remains responsible for the grid, its operation, maintenance and investment plans) are addressed.

The repetitive stacked Blumlein pulse powergenerators developed at the University of Texas at Dallas consist of several triaxial Blumleins stacked in series at one end. The lines are charged in parallel and synchronously commuted with a single switch at the other end. In this way, relatively low charging voltages are multiplied to give a high discharge voltage across an arbitrary load. Extensive characterization of these novel pulsers have been performed over the past few years. Results indicate that they are capable of producing high power waveforms with rise times and repetition rates in the range of 0.5-50 ns and 1-300 Hz, respectively, using a conventional thyratron, spark gap, or photoconductive switch. The progress in the development and use of stacked Blumlein pulse generators is reviewed. The technology and the characteristics of these novel pulsers driving flash x-ray diodes are discussed. (author). 4 figs., 5 refs.

During the last few years there is an increasing interest on the development of alternative high power new negative ion source for Tokamak applications. The proposed new neutral beam device presents a number of advantages with respect to: the density current, the acceleration voltage, the relative compact dimension of the negative ion source, and the coupling of a high power laser beam for photo-neutralization of the negative ion beam. Here we numerically investigate, using a multi- fluid 1-D code, the acceleration and the extraction of high power ion beam from a Magnetically Insulated Diode (MID). The diode configuration will be coupled to a high power device capable of extracting a current up to a few kA with an accelerating voltage up to MeV. An efficiency of up to 92% of the coupling of the laser beam, is required in order to obtain a high power, up to GW, neutral beam. The new high energy, high average power, high efficiency (up to 30%) ICAN fiber laser is proposed for both the plasma generation and the photo-neutralizer configuration. (authors)

This paper examines the contractual and mandated powergeneration pricing relationships between an electric utility and unregulated powergeneration stations. The topics of the paper include types of generation facilities, current capacity of unregulated generators, rights to power markets, utility planning, responding to a changing market, power purchase agreement relationships, enforcement and renegotiation

This paper presents an intelligent control method for the maximumpower point tracking (MPPT) of a photovoltaic system under variable temperature and irradiance conditions. First, for the purpose of comparison and because of its proven and good performances, the perturbation and observation (P and O) technique is briefly introduced. A fuzzy logic controller based MPPT (FLC) is then proposed which has shown better performances compared to the P and O MPPT based approach. The proposed FLC has been also improved using genetic algorithms (GA) for optimisation. Different development stages are presented and the optimized fuzzy logic MPPT controller (OFLC) is then simulated and evaluated, which has shown better performances. (author)

This work presents a new maximumpower point tracker system for photovoltaic applications. The developed system is an analog version of the ''P and O-oriented'' algorithm. It maintains its main advantages: simplicity, reliability and easy practical implementation, and avoids its main disadvantages: inaccurateness and relatively slow response. Additionally, the developed system can be implemented in a practical way at a low cost, which means an added value. The system also shows an excellent behavior for very fast variables in incident radiation levels. (author)

Earthquake problems associated with the construction of nuclear powergenerators require a more extensive and a more precise knowledge of earthquake characteristics and the dynamic behavior of structures than was considered necessary for ordinary buildings. Economic considerations indicate the desirability of additional research on the problems of earthquakes and nuclear reactors. The nature of these earthquake-resistant design problems is discussed and programs of research are recommended. (auth)

In this paper production data of wind power in Europe and Bulgaria and plans for their development within 2030 are reviewed. The main characteristics of wind generators used in Bulgaria are listed. A review of the grid code in different European countries, which regulate the requirements for renewable sources, is made. European recommendations for requirements harmonization are analyzed. Suggestions for the Bulgarian gird code are made

Investigations were carried out to determine the feasibility of volcanic powergeneration on Satsuma Io Island. Earthquakes were studied, as were the eruptions of subaerial and submarine hot springs. Hydrothermal rock alteration was studied and electrical surveys were made. General geophysical surveying was performed with thermocameras and radiation monitoring equipment. In particular, the Toyoba mine was studied, both with respect to its hot spring and its subsurface temperatures.

Full text: The beginning of the third millennium has been characterized by a progressive increase in the demand for fossil fuels, which has caused a steep rise in oil price. At the same time, several environmental disasters have increased the sensitivity of world-wide public opinion towards the effect that environmental pollution has on human health and climate change. These conditions have fostered a renewed interest in renewable energy like solar energy, wind energy, biomass and solid wastes. In addition, the disposal of municipal solid waste (MSW) has become a critical and costly problem. The traditional landfill method requires large amounts of land and contaminates air, water and soil. The increase in socio-economic condition during the past ten years has also significantly increased the amount of solid waste generated. There are around 1200 tons of municipal solid waste (MSW) generated daily, of which the combustibles namely plastics, paper and textile waste represent 28%, and with the present generation rate, the landfill will be filled by 2012. The study was, therefore, initiated to assess the potential of powergeneration from refused derived fuels (RDF) from municipal solid waste (MSW) in order to reduce the dependency on fossil fuels. There are 336 tons which is equivalent to 12 tons/ h of RDF that can be generated daily from the MSW and this would generate 19.2 MW power. There will be 312 kg/ h of ash that would be generated and the NO x and SO 2 concentration were found to be 395.5 and 43.3 mg/ Nm 3 respectively. It was also found that the amount of non-biogenic CO 2 produced was 471 g/ kWhe. (author)

Photovoltaic powergeneration is an attractive source of energy since it involves the direct conversion of sunlight into electricity with no moving parts and no pollution. Following the demonstration of the first solar cell 35 years ago at Bell Laboratories, a steady stream of scientific and commercial progress has led to a rapid increase in applications in recent years. The first commercial application of solar cells occurred more than 20 years ago when they were used to supply power for space satellites, and even today photovoltaic arrays are used to supply electricity for most satellites and space probes. This paper reviews the status of the various photovoltaic technologies as well as present applications. The prospects for both distributed and central station grid-connected systems are discussed. The paper concludes with a discussion of the institutional and political factors that will affect the introduction of grid-connected photovoltaic power systems

The author reports photovoltaic powergeneration is an attractive source of energy since it involves the direct conversion of sunlight into electricity with no moving parts and no pollution. Following the demonstration of the first solar cell 35 years ago at Bell Laboratories, a steady stream of scientific and commercial progress has led to a rapid increase in applications in recent years. The first commercial application of solar cells occurred more than 20 years ago when they were used to supply power for space satellites, and even today photovoltaic arrays are used to supply electricity for most satellites and space probes. This paper reviews the status of the various photovoltaic technologies as well as present applications. The prospects for both distributed and central station grid-connected systems are discussed. The paper concludes with a discussion of the institutional and political factors that will affect the introduction of grid-connected photovoltaic power systems

A polymer electrolyte fuel cell (PEFC) powergeneration system using pure hydrogen was developed by Toshiba International Fuel Cells (TIFC), Japan, under the sponsorship of the World Energy Network (WE-NET) Project. The goals of the project consist of the construction of 30 kilowatt powergeneration plant for stationary application and target electrical efficiency of over 50 per cent. Two critical technologies were investigated for high utilization stack, as high hydrogen utilization operation represents one of the most important items for the achievement of target efficiency. The first technology examined was the humidification method from cathode side, while the second was the two-block configuration, which is arranged in series in accordance with the flow of hydrogen. Using these technologies as a basis for the work, a 5 kilowatt short stack was developed, and a steady performance was obtained under high hydrogen utilization of up to 98 per cent. It is expected that by March 2003 the design of the hydrogen fueled 30 kilowatt powergeneration plant will be completed and assembled. 1 ref., 1 tab., 11 figs.

The Obrigheim Nuclear Power Station (KWO) is equipped with a dual-loop pressurized water reactor of 345 MW electric power; it was built by Siemens in the period 1965 to 1968. By the end of 1983, KWO had produced some 35 billion kWh in 109,000 hours of operation. Repeated leaks in the heater tubes of the two steam generators had occurred since 1971. Both steam generators were replaced in the course of the 1983 annual revision. Kraftwerk Union AG (KWU) was commissioned to plant and carry out the replacement work. Despite the leakages the steam generators had been run safely and reliably over a period of 14 years until their replacement. Replacing the steam generators was completed within twelve weeks. In addition to the KWO staff and the supervising crew of KWU, some 400 external fitters were employed on the job at peak work-load periods. For the revision of the whole plant, work on the emergency systems and replacement of the steam generators a maximum number of approx. 900 external fitters were employed in the plant in addition to some 250 members of the plant crew. The exposure dose of the personnel sustained in the course of the steam generator replacement was 690 man-rem, which was clearly below previous estimates. (orig.) [de

Furfural is a typical inhibitor in the ethanol fermentation process using lignocellulosic hydrolysates as raw materials. In the literature, no report has shown that furfural can be utilized as the fuel to produce electricity in the microbial fuel cell (MFC), a device that uses microbes to convert organic compounds to generate electricity. In this study, we demonstrated that electricity was successfully generated using furfural as the sole fuel in both the ferricyanide-cathode MFC and the air-cathode MFC. In the ferricyanide-cathode MFC, the maximumpower densities reached 45.4, 81.4, and 103 W m{sup -3}, respectively, when 1000 mg L{sup -1} glucose, a mixture of 200 mg L{sup -1} glucose and 5 mM furfural, and 6.68 mM furfural were used as the fuels in the anode solution. The corresponding Coulombic efficiencies (CE) were 4.0, 7.1, and 10.2% for the three treatments, respectively. For pure furfural as the fuel, the removal efficiency of furfural reached up to 95% within 12 h. In the air-cathode MFC using 6.68 mM furfural as the fuel, the maximum values of power density and CE were 361 mW m{sup -2} (18 W m{sup -3}) and 30.3%, respectively, and the COD removal was about 68% at the end of the experiment (about 30 h). Increase in furfural concentrations from 6.68 to 20 mM resulted in increase in the maximumpower densities from 361 to 368 mW m{sup -2}, and decrease in CEs from 30.3 to 20.6%. These results indicated that some toxic and biorefractory organics such as furfural might still be suitable resources for electricity generation using the MFC technology. (author)

The main objective of this work is to provide an overview and evaluation of discrete model predictive controlbased maximumpower point tracking (MPPT) for PV systems. A large number of MPC based MPPT methods have been recently introduced in the literature with very promising performance, however......, an in-depth investigation and comparison of these methods have not been carried out yet. Therefore, this paper has set out to provide an in-depth analysis and evaluation of MPC based MPPT methods applied to various common power converter topologies. The performance of MPC based MPPT is directly linked...... with the converter topology, and it is also affected by the accurate determination of the converter parameters, sensitivity to converter parameter variations is also investigated. The static and dynamic performance of the trackers are assessed according to the EN 50530 standard, using detailed simulation models...

Solar panels have a nonlinear voltage-current characteristic, with a distinct maximumpower point (MPP), which depends on the environmental factors, such as temperature and irradiation. In order to continuously harvest maximumpower from the solar panels, they have to operate at their MPP despite the inevitable changes in the environment. Various methods for maximumpower point tracking (MPPT) were developed and finally implemented in solar power electronic controllers to increase the efficiency in the electricity production originate from renewables. In this paper we compare using Matlab tools Simulink, two different MPP tracking methods, which are, fuzzy logic control (FL) and sliding mode control (SMC), considering their efficiency in solar energy production.

Nuclear power represents a major portion of Ontario PowerGeneration's generation mix and it will be the bedrock upon which we build a successful, competitive company. Our nuclear units offer many environmental and economic benefits, the one most relevant to this meeting is their significant contribution to the relatively low carbon intensity of Ontario's and Canada's electricity supply. In recent weeks, we have listened with great interest to the endorsement by our federal Minister of the Environment of nuclear technology as a means of reducing global warming. But endorsements of this type alone are not sufficient to ensure that nuclear remains an acceptable option for managing greenhouse gas emissions. Without public acceptance and support, the entire nuclear investment is endangered. At OPG we face three challenges to building this public support: we must continue to improve our safety margins and operating performance; we must continue to improve the environmental performance at our stations; and we must increase our community outreach. Today I would like to focus on the last two challenges and the actions that we are taking to maintain our social and environmental 'licence to operate.' But before I describe these initiatives, I will tell you about: the new company - Ontario PowerGeneration; the changes in store for Ontario's electricity sector; and our greenhouse gas emissions - the legacy from Ontario Hydro. (author)

The purposes of the steam generator repair program at Surry Power Station were to repair the tube degradation caused by corrosion-related phenomena and to restore the integrity of the steam generators to a level equivalent to new equipment. The repair program consisted of (1) replacing the existing lower-shell assemblies with new ones and (2) adding new moisture separation equipment to the upper-shell assemblies. These tasks required that several pieces of reactor coolant piping, feedwater piping, main steam piping, and the steam generator be cut and refurbished for reinstallation after the new lower shell was in place. The safety implications and other potential effects of the repair program both during the repair work and after the unit was returned to power were part of the design basis of the repair program. The repair program has been completed on Unit 2 without any adverse effects on the health and safety of the general public or to the personnel engaged in the repair work. Before the Unit 1 repair program began, a review of work procedures and field changes for the Unit 2 repair was conducted. Several major changes were made to avoid recurrence of problems and to streamline procedures. Steam generator replacements was completed on June 1, 1981, and the unit is presently in the startup phase of the outrage

Security of supply of electric energy is measured by the capacity to cover the energy demand and power of a supply grid. This coverage is important because the winter peak load period in Switzerland will become problematical in the near future. The objective of this research project is to analyze the ability of a powergenerating system to satisfy the power requirements of the corresponding supply network. The behaviour of the energy system in critical cases (loss of the largest generator, lack of available power from an external supplier or reduced capacity for energy storage) is tested for the present situation and for the rise in the annual load. The simulation of the load of the supply network is carried out by using a model developed for this project. This model is based on the analysis of half-hourly changes of load and on the statistical maximum values. The powergenerating system consists of nuclear generating units, hydro units with large reservoirs, run of the river installations and imported energy. Standby units such as gas turbines, spot market and coal-fired power stations are also available. Stochastic and deterministic energy and power models have been developed for the various power stations of the hydrothermal power system. In the case of nuclear power stations, a model has been developed on the basis of the output level, production losses and time and length of outages. The possible feeder streams of the run of the river installations and of the hydro units with a large reservoir are simulated using stochastic methods based on the historical values of the last 35 years. The commitment of the hydro units depends on the peak load requirements. The load and capacity over a period of several days and weeks have been simulated with stochastic models based on the Monte Carlo method and constantly (by half hour intervals) compared. In this manner each month can be simulated. (author) figs., tabs., 46 refs

Conceptual study on a demonstration plant for electric powergeneration, named Demo-CREST, was conducted based on the consideration that a demo-plant should have capacities both (1) to demonstrate electric powergeneration in a plant scale with moderate plasma performance, which will be achieved in the early stage of the ITER operation, and foreseeable technologies and materials and (2) to have a possibility to show an economical competitiveness with advanced plasma performance and high performance blanket systems. The plasma core was optimized to be a minimum size for both net electric powergeneration with the ITER basic plasma parameters and commercial-scale generation with advance plasma parameters, which would be attained by the end of ITER operation. The engineering concept, especially the breeding blanket structure and its maintenance scheme, is also optimized to demonstrate the tritium self-sustainability and maintainability of in-vessel components. Within the plasma performance as planned in the present ITER program, the net electric power from 0 MW to 500 MW is possible with the basic blanket system under the engineering conditions of maximum magnetic field 16 T, NBI system efficiency 50%, and NBI current drive power restricted to 200 MW. Capacities of stabilization of reversed shear plasma and the high thermal efficiency are additional factors for optimization of the advanced blanket. By replacing the blanket system with the advanced one of higher thermal efficiency, the net electric power of about 1000 MW is also possible so that the economic performance toward the commercial plant can be also examined with Demo-CREST. (author)

This study presents a prototype thermoelectric generator (TEG) developed for remote applications in villages that are not connected to the electrical power grid. For ecological and economic reasons, there is growing interest in harvesting waste heat from biomass stoves to produce some electricity. Because regular maintenance is not required, TEGs are an attractive choice for small-scale powergeneration in inaccessible areas. The prototype developed in our laboratory is especially designed to be implemented in stoves that are also used for domestic hot water heating. The aim of this system is to provide a few watts to householders, so they have the ability to charge cellular phones and radios, and to get some light at night. A complete prototype TEG using commercial (bismuth telluride) thermoelectric modules has been built, including system integration with an electric DC/DC converter. The DC/DC converter has a maximumpower point tracker (MPPT) driven by an MC9SO8 microcontroller, which optimizes the electrical energy stored in a valve-regulated lead-acid battery. Physical models were used to study the behavior of the thermoelectric system and to optimize the performance of the MPPT. Experiments using a hot gas generator to simulate the exhaust of the combustion chamber of a stove are used to evaluate the system. Additionally, potential uses of such generators are presented.

Solar photovoltaic (PV) arrays in remote applications are often related to the rapid changes in the partial shading pattern. Rapid changes of the partial shading pattern make the tracking of maximumpower point (MPP) of the global peak through the local ones too difficult. An essential need to make a fast and efficient algorithm to detect the peaks values which always vary as the sun irradiance changes. This paper presents two algorithms based on the improved particle swarm optimization technique one of them with PID controller (IPSO-PID), and the other one with Brain Emotional Learning Based Intelligent Controller (IPSO-BELBIC). These techniques improve the maximumpower point (MPP) tracking capabilities for photovoltaic (PV) system under partial shading circumstances. The main aim of these improved algorithms is to accelerate the velocity of IPSO to reach to (MPP) and increase its efficiency. These algorithms also improve the tracking time under complex irradiance conditions. Based on these conditions, the tracking time of these presented techniques improves to 2 msec, with an efficiency of 100%.

Full Text Available This study proposed an adaptive double-integral-sliding-mode-controller-maximum-power-point tracker (DISMC-MPPT for maximum-power-point (MPP tracking of a photovoltaic (PV system. The objective of this study is to design a DISMC-MPPT with a new adaptive double-integral-sliding surface in order that MPP tracking is achieved with reduced chattering and steady-state error in the output voltage or current. The proposed adaptive DISMC-MPPT possesses a very simple and efficient PWM-based control structure that keeps switching frequency constant. The controller is designed considering the reaching and stability conditions to provide robustness and stability. The performance of the proposed adaptive DISMC-MPPT is verified through both MATLAB/Simulink simulation and experiment using a 0.2 kW prototype PV system. From the obtained results, it is found out that this DISMC-MPPT is found to be more efficient compared with that of Tan's and Jiao's DISMC-MPPTs.

Solar photovoltaic (PV) arrays in remote applications are often related to the rapid changes in the partial shading pattern. Rapid changes of the partial shading pattern make the tracking of maximumpower point (MPP) of the global peak through the local ones too difficult. An essential need to make a fast and efficient algorithm to detect the peaks values which always vary as the sun irradiance changes. This paper presents two algorithms based on the improved particle swarm optimization technique one of them with PID controller (IPSO-PID), and the other one with Brain Emotional Learning Based Intelligent Controller (IPSO-BELBIC). These techniques improve the maximumpower point (MPP) tracking capabilities for photovoltaic (PV) system under partial shading circumstances. The main aim of these improved algorithms is to accelerate the velocity of IPSO to reach to (MPP) and increase its efficiency. These algorithms also improve the tracking time under complex irradiance conditions. Based on these conditions, the tracking time of these presented techniques improves to 2 msec, with an efficiency of 100%.

This article reports on the design and performance analysis of a solar thermoelectric powergeneration plant (STEPG). The system considers both truncated compound parabolic collectors (CPCs) with a flat receiver and conventional flat-plate collectors, thermoelectric (TE) cooling and powergenerator modules and appropriate connecting pipes and control devices. The design tool uses TRNSYS IIsibat-15 program with a new component we developed for the TE modules. The main input data of the system are the specifications of TE module, the maximum hot side temperature of TE modules, and the desired power output. Examples of the design using truncated CPC and flat-plate collectors are reported and discussed for various slope angle and half-acceptance angle of CPC. To minimize system cost, seasonal adjustment of the slope angle between 0° and 30° was considered, which could give relatively high power output under Bangkok ambient condition. Two small-scale STEPGs were built. One of them uses electrical heater, whereas the other used a CPC with locally made aluminum foil reflector. Measured data showed reasonable agreement with the model outputs. TE cooling modules were found to be more appropriate. Therefore, the TRNSYS software and the developed TE component offer an extremely powerful tool for the design and performance analysis of STEPG plant.

Stirling Radioisotope Power Systems (RPS) are being developed as an option to provide power on future space science missions where robotic spacecraft will orbit, flyby, land or rove. A Stirling Radioisotope Generator (SRG) could offer space missions a more efficient power system that uses one fourth of the nuclear fuel and decreases the thermal footprint of the current state of the art. The RPS Program Office, working in collaboration with the U.S. Department of Energy (DOE), manages projects to develop thermoelectric and dynamic power systems, including Stirling Radioisotope Generators (SRGs). The Stirling Cycle Technology Development (SCTD) Project, located at Glenn Research Center (GRC), is developing Stirling-based subsystems, including convertors and controllers. The SCTD Project also performs research that focuses on a wide variety of objectives, including increasing convertor temperature capability to enable new environments, improving system reliability or fault tolerance, reducing mass or size, and developing advanced concepts that are mission enabling. Research activity includes maturing subsystems, assemblies, and components to prepare them for infusion into future convertor and generator designs. The status of several technology development efforts are described here. As part of the maturation process, technologies are assessed for readiness in higher-level subsystems. To assess the readiness level of the Dual Convertor Controller (DCC), a Technology Readiness Assessment (TRA) was performed and the process and results are shown. Stirling technology research is being performed by the SCTD Project for NASA's RPS Program Office, where tasks focus on maturation of Stirling-based systems and subsystems for future space science missions.

This paper outlined a procedure for obtaining data to facilitate air and noise compliance assessments for emergency and other fuel-fired powergenerators. Facilities with the generators may contain additional sources of nitrogen oxides (NO x ). The assessments are required for each new or modified generator in order to ensure that regulatory requirements in the Air Pollution Local Air Quality Regulation and the Noise Pollution Control documents are met. The air emission assessments follow the Ontario Ministry of the Environment (MOE) report. The paper included a screening process to screen out generators with negligible emissions. A maximumpower rating was calculated using AP-2 emission factors and a conservative heat rating assumption. Maximumpower ratings for various types of generators were presented. The information requirements included a description of the type of engine used; sound power level data; octave band insertion loss data; and plan and section drawings of the generator room. 2 tabs.

We revisit the problem of exact cosmic microwave background (CMB) likelihood and power spectrum estimation with the goal of minimizing computational costs through linear compression. This idea was originally proposed for CMB purposes by Tegmark et al., and here we develop it into a fully functioning computational framework for large-scale polarization analysis, adopting WMAP as a working example. We compare five different linear bases (pixel space, harmonic space, noise covariance eigenvectors, signal-to-noise covariance eigenvectors, and signal-plus-noise covariance eigenvectors) in terms of compression efficiency, and find that the computationally most efficient basis is the signal-to-noise eigenvector basis, which is closely related to the Karhunen-Loeve and Principal Component transforms, in agreement with previous suggestions. For this basis, the information in 6836 unmasked WMAP sky map pixels can be compressed into a smaller set of 3102 modes, with a maximum error increase of any single multipole of 3.8% at ℓ ≤ 32 and a maximum shift in the mean values of a joint distribution of an amplitude-tilt model of 0.006σ. This compression reduces the computational cost of a single likelihood evaluation by a factor of 5, from 38 to 7.5 CPU seconds, and it also results in a more robust likelihood by implicitly regularizing nearly degenerate modes. Finally, we use the same compression framework to formulate a numerically stable and computationally efficient variation of the Quadratic Maximum Likelihood implementation, which requires less than 3 GB of memory and 2 CPU minutes per iteration for ℓ ≤ 32, rendering low-ℓ QML CMB power spectrum analysis fully tractable on a standard laptop.

Kuwait is facing a surge in the consumption of power. The current power fuel mix, based on oil, appears unsustainable. Yet Kuwait has a large number of assets. The power fuel mix can be optimized and diversified to include alternatives to oil such as gas or renewables, so as to benefit from the opportunity cost of oil (the price at which this oil could be sold on international market). The country has gas reserves and a good potential in renewable technologies. If energy efficiency can be considered as a potential resource, then much can be achieved in this area as well, given Kuwait's current power and water per capita consumption rates, which are among the highest in the world. The present tendency has been to go for step-by-step fixes, adding emergency power plants which have increased powergeneration costs and a non-optimized system. Kuwait is on the verge of defining a new power fuel mix, with more gas, and developing new R and D projects. In this context, this memorandum looks at alternatives, and concludes that in the long term a diversified power mix has to be developed. The current gas glut at the world level, resulting both from the production of unconventional gas resources and the economic recession hitting Europe, offers a sizable opportunity for gas imports. A transition strategy for the power sector could make use of gas imports. In the longer term, however, Kuwait should not make a one-way bet and develop its domestic gas resources. This paper urges the adoption of a common gas strategy integrated into a power sector strategy, through consultation with all actors. It would include reserves, costs, feasibility and potential uses, as well as economic opportunities. As the region is facing gas shortages and Kuwait ranks independence of supply among its policy priorities, renewable, and in particular solar have their own place in the power mix. The country indeed disposes of substantial and relatively predictable renewable energy resources. Those are

Reverse electrodialysis (RED) can harness the Gibbs free energy of mixing when fresh river water flows into the sea for sustainable powergeneration. In this study, we carry out a thermodynamic and energy efficiency analysis of RED powergeneration, and assess the membrane power density. First, we present a reversible thermodynamic model for RED and verify that the theoretical maximum extractable work in a reversible RED process is identical to the Gibbs free energy of mixing. Work extraction in an irreversible process with maximized power density using a constant-resistance load is then examined to assess the energy conversion efficiency and power density. With equal volumes of seawater and river water, energy conversion efficiency of ∼ 33-44% can be obtained in RED, while the rest is lost through dissipation in the internal resistance of the ion-exchange membrane stack. We show that imperfections in the selectivity of typical ion exchange membranes (namely, co-ion transport, osmosis, and electro-osmosis) can detrimentally lower efficiency by up to 26%, with co-ion leakage being the dominant effect. Further inspection of the power density profile during RED revealed inherent ineffectiveness toward the end of the process. By judicious early discontinuation of the controlled mixing process, the overall power density performance can be considerably enhanced by up to 7-fold, without significant compromise to the energy efficiency. Additionally, membrane resistance was found to be an important factor in determining the power densities attainable. Lastly, the performance of an RED stack was examined for different membrane conductivities and intermembrane distances simulating high performance membranes and stack design. By thoughtful selection of the operating parameters, an efficiency of ∼ 37% and an overall gross power density of 3.5 W/m(2) represent the maximum performance that can potentially be achieved in a seawater-river water RED system with low

Increasing levels of penetration of wind power and other renewable generations in European power systems pose challenges to power system security. The power system operators are continuously challenged especially when generations from renewables are high thereby reducing online capacity of conven......Increasing levels of penetration of wind power and other renewable generations in European power systems pose challenges to power system security. The power system operators are continuously challenged especially when generations from renewables are high thereby reducing online capacity......, one of them being the North East area with high share of wind powergeneration.The aim of this study is to investigate how renewable generations like wind power can contribute to the power system defence plans. This PhD project “Integration of Renewable Generation in Power System Defence Plans...

In order to prevent global warming, attention is focused on nuclear powergeneration and renewable energy such as wind and solar powergeneration. The electric power suppliers of Japan are aiming to increase the amount of nuclear and non-fossil fuel powergeneration over 50% of the total powergeneration by 2020. But this means that the remaining half will still be of thermal powergeneration using fossil fuel and will still play an important role. Under such circumstances, further efficiency improvement of the thermal powergeneration and its aggressive implementation is ongoing in Japan.

A proposed microelectromechanical system (MEMS) containing a closed- Brayton-cycle turbine would serve as a prototype of electric-powergenerators for special applications in which high energy densities are required and in which, heretofore, batteries have been used. The system would have a volume of about 6 cm3 and would operate with a thermal efficiency >30 percent, generating up to 50 W of electrical power. The energy density of the proposed system would be about 10 times that of the best battery-based systems now available, and, as such, would be comparable to that of a fuel cell. The working gas for the turbine would be Xe containing small quantities of CO2, O2, and H2O as gaseous lubricants. The gas would be contained in an enclosed circulation system, within which the pressure would typically range between 5 and 50 atm (between 0.5 and 5 MPa). The heat for the Brayton cycle could be supplied by any of a number of sources, including a solar concentrator or a combustor burning a hydrocarbon or other fuel. The system would include novel heat-transfer and heat-management components. The turbine would be connected to an electric powergenerator/starter motor. The system would include a main rotor shaft with gas bearings; the bearing surfaces would be made of a ceramic material coated with nanocrystalline diamond. The shaft could withstand speed of 400,000 rpm or perhaps more, with bearing-wear rates less than 10(exp -)4 those of silicon bearings and 0.05 to 0.1 those of SiC bearings, and with a coefficient of friction about 0.1 that of Si or SiC bearings. The components of the system would be fabricated by a combination of (1) three-dimensional xray lithography and (2) highly precise injection molding of diamond-compatible metals and ceramic materials. The materials and fabrication techniques would be suitable for mass production. The disadvantages of the proposed system are that unlike a battery-based system, it could generate a perceptible amount of sound, and

Sarnoff has designed an integrated array of thermophotovoltaic (TPV) cells based on the In(Al)GaAsSb/GaSb materials system. These arrays will be used in a system to generate electrical power from a radioisotope heat source that radiates at temperatures from 700 to 1000 C. Two arrays sandwich the slab heat source and will be connected in series to build voltage. Between the arrays and the heat source is a spectral control filter that transmits above-bandgap radiation and reflects below-bandgap radiation. The goal is to generate 5 mW of electrical power at 3 V from a 700 C radiant source. Sarnoff is a leader in antimonide-based TPV cell development. InGaAsSb cells with a bandgap of 0.53 eV have operated at system conversion efficiencies greater than 17%. The system included a front-surface filter, and a 905 C radiation source. The cells were grown via organo-metallic vapor-phase epitaxy. Sarnoff will bring this experience to bear on the proposed project. The authors first describe array and cell architecture. They then present calculated results showing that about 80 mW of power can be obtained from a 700 C radiator. Using a conservative array design, a 5-V output is possible

Present status and development of wind powergeneration in China is described in this paper. China is vast in territory with abundant wind resources. The exploitable wind energy in China is estimated up to 253,000 MW. At present, more than 150 thousand small WTGs of a total capacity of 17 MW are used to provide residential electricity uses in non-grid connected areas and 13 wind farms, with above 160 medium and large scale grid connected WTGs (50-500 kW) of a total capacity of 30 MW, have been constructed. At the same time, some progress has been made in the fields of nation-wide wind resource assessment, measurement technology of wind turbine performance, the assimilation of foreign wind turbine technology, grid connected WTG technology and the operation of wind farm etc. It is planned that the total installed capacity of WTGs will reach 1000 MW by the end of 2000. Wind powergeneration could be a part of electric power industry in China. (Author)

A thermoelectric powergenerator consists of an oven box and a solar cooker/solar reflector unit. The solar reflector concentrates sunlight into heat and transfers the heat into the oven box via a heat pipe. The oven box unit is surrounded by five thermoelectric modules and is located at the bottom end of the solar reflector. When the heat is pumped into one side of the thermoelectric module and ejected from the opposite side at ambient temperatures, an electrical current is produced. Typical temperature accumulation in the solar reflector is approximately 200 C (392 F). The heat pipe then transfers heat into the oven box with a loss of about 40 percent. At the ambient temperature of about 20 C (68 F), the temperature differential is about 100 C (180 F) apart. Each thermoelectric module, generates about 6 watts of power. One oven box with five thermoelectric modules produces about 30 watts. The system provides power for unattended instruments in remote areas, such as space colonies and space vehicles, and in polar and other remote regions on Earth.

Since the occurrence of the petroleum crisis, many countries have devoted a great deal of effort to search for substitute energy sources. Aside from nuclear energy, forms of powergeneration with wind, solar energy, and geothermal energy have all been actually adopted in one place or another. Most recently, a research report was published by the Canadian Bureau of Nuclear Energy Management stating that the use of wind and solar energy to generate electricity is much more dangerous than powergeneration with nuclear energy. When mining, transportation, machine manufacturing, etc. are included in the process of producing unit power, i.e. kilowatt/year, the data of various risks of death, injury, and diseases are computed in terms of man/day losses by the bureau. They indicate that of the ten forms of powergeneration, the danger is the least with natural gas, only about a 6 man/day, and nuclear energy is the next least dangerous, about 10 man/day. The danger of using temperature differential of sea water to generate electricity is about 25 man/day, and the most dangerous form of powergeneration is coal, amounting to three thousand man/day.

Highlights: • Approach to estimate the state of maximumpower available in Lithium-Ion battery. • Optimisation problem is formulated on the basis of a non-linear dynamic model. • Solutions of the optimisation problem are functions of state of charge estimates. • State of charge estimates computed using particle filter algorithms. - Abstract: Battery Energy Storage Systems (BESS) are important for applications related to both microgrids and electric vehicles. If BESS are used as the main energy source, then it is required to include adequate procedures for the estimation of critical variables such as the State of Charge (SoC) and the State of Health (SoH) in the design of Battery Management Systems (BMS). Furthermore, in applications where batteries are exposed to high charge and discharge rates it is also desirable to estimate the State of MaximumPower Available (SoMPA). In this regard, this paper presents a novel approach to the estimation of SoMPA in Lithium-Ion batteries. This method formulates an optimisation problem for the battery power based on a non-linear dynamic model, where the resulting solutions are functions of the SoC. In the battery model, the polarisation resistance is modelled using fuzzy rules that are function of both SoC and the discharge (charge) current. Particle filtering algorithms are used as an online estimation technique, mainly because these algorithms allow approximating the probability density functions of the SoC and SoMPA even in the case of non-Gaussian sources of uncertainty. The proposed method for SoMPA estimation is validated using the experimental data obtained from an experimental setup designed for charging and discharging the Lithium-Ion batteries.

Free-piston Stirling engines are an interesting alternative for electrical power systems, especially in deep space missions where photovoltaic systems are not feasible. This kind of powergenerators contains two main parts, the Stirling machine and the linear alternator that converts the mechanical energy from the piston movement to electrical energy. Since the generatedpower is in AC form, several aspects should be assessed to use such kind of generators in a spacecraft power system: AC/DC topologies, power factor correction, power regulation techniques, integration into the power system, etc. This paper details powergenerator operation and explores different power conversion approaches.

This paper describes different systems of small wind power plants with induction generators used in the Czech Republic. Problems of wind power plants running with induction generators are solved within partial target of the research project MSM 6198910007. For small wind power plants is used induction motor as a generator. Parameters of the name plate of motor must be resolved for generator running on measuring base. These generators are running as a separately working generators or generator...

A trade of figure of merit (\\dotΩ ) criterion accounts the best compromise between the useful input energy and the lost input energy of the heat devices. When the heat engine is working at maximum \\dotΩ criterion its efficiency increases significantly from the efficiency at maximumpower. We derive the general relations between the power, efficiency at maximum \\dotΩ criterion and minimum dissipation for the linear irreversible heat engine. The efficiency at maximum \\dotΩ criterion has the lower bound \

In spite of the fact that analyses of the cost of electric powergeneration as the result of international comparative evaluations are indisputably relevant, problems pending in connection with the costs of representative power plant technologies are of the methodological bind. German authors have hitherto also been failing to clear up and consider all aspects connected with the problems of data acquisition and the adequate interpretation of results. The analysis presented by the paper abstracted therefore aims at the following: 1) Systematization of the different categories of cost relevant in connection with international comparative evaluation. Classification into different categories of decision making and development of standards meeting the requirements of international comparative evaluation. 2) Calculation of relevant average financial costs of Western German, America and French fossil-fuel and nuclear power plants by means of adequate calculation models, that is the assessment of costs with regard to countries and power plant technologies which are relevant to the Federal Republic of Germany. 3) Analysis of the resulting differences and determinantal interpretation. (orig./UA) [de

Using fossil fuels is likely to remain the dominant means of producing electricity in 2030 and even 2050, partly because power stations have long lives. There are two main ways of reducing CO 2 emissions from fossil-fuelled power plants. These are carbon capture and storage (CCS), which can produce near-zero CO 2 emissions, and increases in plant efficiency, which can give rise to significant reductions in CO 2 emissions and to reduced costs. If a typical UK coal-fired plant was replaced by today's best available technology, it would lead to reductions of around 25% in emissions of CO 2 per MW h of electricity produced. Future technologies are targeting even larger reductions in emissions, as well as providing a route, with CCS, to zero emissions. These two routes are linked and they are both essential activities on the pathway to zero emissions. This paper focuses on the second route and also covers an additional third route for reducing emissions, the use of biomass. It discusses the current status of the science and technologies for fossil-fuelled powergeneration and outlines likely future technologies, development targets and timescales. This is followed by a description of the scientific and technological developments that are needed to meet these challenges. Once built, a power plant can last for over 40 years, so the ability to upgrade and retrofit a plant during its lifetime is important

In two decades, three momentous changes have occurred that will influence powergeneration for decades to come. Coal has become a culprit responsible for respiratory disease and acid rain; carbon dioxide has become a culprit widely believed capable of changes in climate greater than any that have occurred in ten thousand years; and nuclear power in many countries has become an outcast. The irony is that nuclear power promised clean air and no greenhouse effect. The great gathering of heads of state in Rio in 1992 was the celebration of a problem; whether it was the beginning of a solution remains to be seen. The paper is followed by a discussion by Dominique Finon, Director, Institut d'Economie et de Politique de l'Energie, CNRS and Universite of Grenoble, France. He presents a divergent view to the wait-and-see attitude that appears from Schelling's discourse. He points to the increasing array of technological options available to the power industry and discusses the need for dynamic approaches to problems such as global warming. 5 refs

An apparatus, system, and method for a self-powered device using on-chip powergeneration. In some embodiments, the apparatus includes a substrate, a powergeneration module on the substrate, and a power storage module on the substrate. The powergeneration module may include a thermoelectric generator made of bismuth telluride.

An apparatus, system, and method for a self-powered device using on-chip powergeneration. In some embodiments, the apparatus includes a substrate, a powergeneration module on the substrate, and a power storage module on the substrate. The powergeneration module may include a thermoelectric generator made of bismuth telluride.

The considerable importance that France attributes to nuclear energy is well known even though as a result of the economic crisis and the energy savings it is possible to observe a certain downward trend in the rate at which new power plants are being started up. In July 1983, a symbolic turning-point was reached - at more than 10 thousand million kW.h nuclear power accounted, for the first time, for more than 50% of the total amount of electricity generated, or approx. 80% of the total electricity output of thermal origin. On the other hand, the direct contribution - excluding the use of electricity - of nuclear energy to the heat market in France remains virtually nil. The first part of this paper discusses the prospects and realities of the application, at low and intermediate temperatures, of nuclear heat in France, while the second part describes the French nuclear projects best suited to the heat market (excluding high temperatures). (author)

sources (RES) are commonly recognized as the major driven force of the revolution, the outburst of customer electronics and new kinds of household electronics is also powering this change. In this context, dc power distribution technologies have made a comeback and keep gaining a commendable increase...... in research interests and industrial applications. In addition, the concept of flexible and smart distribution has also been proposed, which tends to exploit distributed generation and pack the distributed RESs and local electrical loads as an independent and self-sustainable entity, namely microgrid....... At present, the research of dc microgrid has investigated and developed a series of advanced methods in control, management and objective-oriented optimization, which would found the technical interface enabling the future applications in multiple industrial areas, such as smart buildings, electric vehicles...

The multi-agent system (MAS) approach has been applied with promising results for enhancing an electric power distribution circuit, such as the Circuit of the Future as developed by Southern California Edison. These next generationpower system results include better ability to reconfigure the circuit as well as the increased capability to improve the protection and enhance the reliability of the circuit. There were four main tasks in this project. The specific results for each of these four tasks and their related topics are presented in main sections of this report. Also, there were seven deliverables for this project. The main conclusions for these deliverables are summarized in the identified subtask section of this report. The specific details for each of these deliverables are included in the “Project Deliverables” section at the end of this Final Report.

The invention concerns a wind power plant which rotates on a vertical axis and is suitable for the generation of electricity. This wind power machine with a vertical axis can be mounted at any height, so that it can catch the wind on the vertical axis of rotation. Further, it does not have to be turned into the direction of the wind and fixed. The purpose of the invention is to obtain equal load on the structure due to the vertical axis. The purpose of the invention is fulfilled by having the wind vanes fixed above one another from the bottom to the top in 6 different directions. The particular advantage of the invention lies in the fact that the auxiliary blades can bring the other blades to the operating position in good time, due to their particular method of fixing.

Full Text Available Partial shading is an unavoidable condition which significantly reduces the efficiency and stability of a photovoltaic (PV system. When partial shading occurs the system has multiple-peak output power characteristics. In order to track the global maximumpower point (GMPP within an appropriate period a reliable technique is required. Conventional techniques such as hill climbing and perturbation and observation (P&O are inadequate in tracking the GMPP subject to this condition resulting in a dramatic reduction in the efficiency of the PV system. Recent artificial intelligence methods have been proposed, however they have a higher computational cost, slower processing time and increased oscillations which results in further instability at the output of the PV system. This paper proposes a fast and efficient technique based on Radial Movement Optimization (RMO for detecting the GMPP under partial shading conditions. The paper begins with a brief description of the behavior of PV systems under partial shading conditions followed by the introduction of the new RMO-based technique for GMPP tracking. Finally, results are presented to demonstration the performance of the proposed technique under different partial shading conditions. The results are compared with those of the PSO method, one of the most widely used methods in the literature. Four factors, namely convergence speed, efficiency (power loss reduction, stability (oscillation reduction and computational cost, are considered in the comparison with the PSO technique.

The important mechanisms of corrosion and corrosion product movement and fouling in the heat transport systems of thermal electric generating stations are reviewed. Oil- and coal-fired boilers are considered, along with nuclear power systems - both direct and indirect cycle. Thus, the fireside and waterside in conventional plants, and the primary coolant and steam-raising circuits in water-cooled reactors, are discussed. Corrosion products in organic- and liquid-metal-cooled reactors also are shown to cause problems if not controlled, while their beneficial effects on the cooling water side of condensers are described. (auth)

This research sought to analyse the market for small scale biogas fuelled distributed powergeneration, to demonstrate the concept of a biogas fuelled microturbine using the Capstone microturbine in conjunction with an anaerobic digester, and undertake a technico-economic evaluation of the biogas fuelled microturbine concept. Details are given of the experimental trials using continuous and batch digesters, and feedstocks ranging from cow and pig slurries to vegetable wastes and municipal solid waste. The yields of methane are discussed along with the successful operation of the microturbine with biogas fuels, and anaerobic digestion projects.

This paper describes the accomplishments of Ontario PowerGeneration (OPG) Nuclear and outlines future opportunities. OPG's mandate is to cost effectively produce electricity, while operating in a safe, open and environmentally responsible manner. OPG's nuclear production has been increasing over the past three years - partly from the addition of newly refurbished Pickering A Units 1 and 4, and partly from the increased production from Darlington and Pickering B. OPG will demonstrate its proficiency and capability in nuclear by continuing to enhance the performance and cost effectiveness of its existing operations. Its priorities are to focus on performance excellence, commercial success, openness, accountability and transparency

This paper discusses the business strategy needed to spark investment in Ontario's powergeneration industry. It examines the process of decision making and investing in an uncertain environment. The paper suggests that any strategy based on one view of the future courts trouble and that strategic flexibility can prepare for what cannot be predicted. Finally the paper suggests that Ontario needs to create a stable policy and regulatory environment that allows investors to fulfill reasonable expectations and investors need to place bets that provide the flexibility to respond quickly to changing market conditions

Describes the British electricity-supply system and covers: the CEGB, nuclear power - AGR design, boiler plant development coal-fired boilers and oil-fired boilers, steam turbine/generators, boiler-feed pumps, pumped storage, gas turbine plants, transmission system including the link to France, the Sizewell-BPWR, future AGR development, future coal-fired stations, fluidized bed combustion, coal gasification, and wind energy developments. Also included is a list of British equipment suppliers to the electricity supply industry, and a buyer's guide to British equipment and services.

This research sought to analyse the market for small scale biogas fuelled distributed powergeneration, to demonstrate the concept of a biogas fuelled microturbine using the Capstone microturbine in conjunction with an anaerobic digester, and undertake a technico-economic evaluation of the biogas fuelled microturbine concept. Details are given of the experimental trials using continuous and batch digesters, and feedstocks ranging from cow and pig slurries to vegetable wastes and municipal solid waste. The yields of methane are discussed along with the successful operation of the microturbine with biogas fuels, and anaerobic digestion projects

The restructuring of the powergeneration industry and the impact it will have on a company`s success was discussed. Some companies are following one of three distinct strategies for survival, the GENCO, MARKETCO and TRADECO. The GENCO focuses on aggregating low cost, kick butt generation assets that could be either regionally concentrated or geographically distributed. The TRADECO invests in few, or even no, assets. Its only objective is to maximize net income. The MARKETCO structure focuses on understanding and meeting customers` needs. The MARKETCO puts as much value in aggregating `load` as it does on assets. It was suggested that the MARKETCO was the quickest path to success in the restructured electric industry, since it is plainly evident that in the New Millenium the customer will be king, and companies will not survive unless they focus the majority of their efforts on the customer.

Sandia National Laboratories has prime responsibility for neutron generator design and manufacturing, and is committed to developing predictive tools for modeling neutron generator performance. An important aspect of understanding component performance is explosively driven ferroelectric power supply modeling. EMMA (ElectroMechanical Modeling in ALEGRA) is a three dimensional compile time version of Sandia's ALEGRA code. The code is built on top of the general ALEGRA framework for parallel shock-physics computations but also includes additional capability for modeling the electric potential field in dielectrics. The overall package includes shock propagation due to explosive detonation, depoling of ferroelectric ceramics, electric field calculation and coupling with a general lumped element circuit equation system. The AZTEC parallel iterative solver is used to solve for the electric potential. The DASPK differential algebraic equation package is used to solve the circuit equation system. Sample calculations are described

Full Text Available Modern trends in development of aircraft engineering go with development of vehicles of the fifth generation. The features of aircrafts of the fifth generation are motivation to use new high-performance systems of onboard power supply. The operating temperature of the outer walls of engines is of 800–1000 K. This corresponds to radiation heat flux of 10 kW/m2 . The thermal energy including radiation of the engine wall may potentially be converted into electricity. The main objective of this paper is to analyze if it is possible to use a high efficiency thermoelectric conversion of heat into electricity. The paper considers issues such as working processes, choice of materials, and optimization of thermoelectric conversion. It presents the analysis results of operating conditions of thermoelectric generator (TEG used in advanced hightemperature power devices. A high-temperature heat source is a favorable factor for the thermoelectric conversion of heat. It is shown that for existing thermoelectric materials a theoretical conversion efficiency can reach the level of 15–20% at temperatures up to 1500 K and available values of Ioffe parameter being ZT = 2–3 (Z is figure of merit, T is temperature. To ensure temperature regime and high efficiency thermoelectric conversion simultaneously it is necessary to have a certain match between TEG power, temperature of hot and cold surfaces, and heat transfer coefficient of the cooling system. The paper discusses a concept of radiation absorber on the TEG hot surface. The analysis has demonstrated a number of potentialities for highly efficient conversion through using the TEG in high-temperature power devices. This work has been implemented under support of the Ministry of Education and Science of the Russian Federation; project No. 1145 (the programme “Organization of Research Engineering Activities”.

The paper demonstrates the characteristics of wind power variability and net load variability in multiple power systems based on real data from multiple years. Demonstrated characteristics include probability distribution for different ramp durations, seasonal and diurnal variability and low net load events. The comparison shows regions with low variability (Sweden, Spain and Germany), medium variability (Portugal, Ireland, Finland and Denmark) and regions with higher variability (Quebec, Bonneville Power Administration and Electric Reliability Council of Texas in North America; Gansu, Jilin and Liaoning in China; and Norway and offshore wind power in Denmark). For regions with low variability, the maximum 1 h wind ramps are below 10% of nominal capacity, and for regions with high variability, they may be close to 30%. Wind power variability is mainly explained by the extent of geographical spread, but also higher capacity factor causes higher variability. It was also shown how wind power ramps are autocorrelated and dependent on the operating output level. When wind power was concentrated in smaller area, there were outliers with high changes in wind output, which were not present in large areas with well-dispersed wind power.

We propose utilization of the nonlinear coupling between the roll and pitch motions of wave energy harvesting vessels to increase their powergeneration by orders of magnitude. Unlike linear vessels that exhibit unidirectional motion, our vessel undergoes both pitch and roll motions in response to frontal waves. This significantly magnifies the motion of the vessel and thus improves the power production by several orders of magnitude. The ocean waves result in roll and pitch motions of the vessel, which in turn causes rotation of an onboard pendulum. The pendulum is connected to an electric generator to produce power. The coupled electro-mechanical system is modeled using energy methods. This paper investigates the powergeneration of the vessel when the ratio between pitch and roll natural frequencies is about 2 to 1. In that case, a nonlinear energy transfer occurs between the roll and pitch motions, causing the vessel to perform coupled pitch and roll motion even though it is only excited in the pitch direction. It is shown that co-existence of pitch and roll motions significantly enhances the pendulum rotation and powergeneration. A method for tuning the natural frequencies of the vessel is proposed to make the energy generator robust to variations of the frequency of the incident waves. It is shown that the proposed method enhances the power output of the floating wave powergenerators by multiple orders of magnitude. A small-scale prototype is developed for the proof of concept. The nonlinear energy transfer and the full rotation of the pendulum in the prototype are observed in the experimental tests.

Electricity generation as an economic sector contributes to the national GDP through increasing investments and exports. In the period from 2000 to 2008 the annual growth rate of final electricity demand was 3,8% which was higher than for any other energy form. Almost 1200 MW of thermal power plants will go out of system due to lifetime (more than 30 years). Energy Strategy is a basic document of the Energy Act with the purpose to define energy policy and future plans for energy development of the Republic of Croatia till 2020. Based on the adopted strategy the Government will create the Energy Strategy Implementation Programme for the four-year period. Croatian's energy development should be based on best available technologies as well as on energy-related, economic and environmental assessment of all available energy options. Energy strategy of Croatia (NN 130/09) puts up next goals: 300 MW hydro power plants (bigger than 10 MW), 1200 MW gas-fired thermal power plants (including 300 MW of cogeneration), 1200 MW of coal-fired thermal power plants, and 35% of renewable (including hydro). The market, i.e. a competitive generation, is the driving force in the construction of new power plants. The main stimulus for the construction is the possibility of definite return of invested capital as well as earning of reasonable profit for investors. Choose of location, environmental impact and competitiveness are main criteria for decision making. Technological and financial terms of new power plant is under influence of the law of supply and demand, so short marginal costs are in the first view - power plant life is at least 30 years - how to deal with this conditions, who will invest in long-term projects with condition of short pay-back period. Climate change and greenhouse gas emissions have become a priority development issue. The main challenge is a long-term development of economy with decreased emission of carbon dioxide. Kyoto protocol obligations, Copenhagen Accord

Technology in power production from biomass has been advancing rapidly. Industry has responded to government incentives such as the PURPA legislation in the US and has recognized that there are environmental advantages to using waste biomass as fuel. During the 1980s many new biomass power plants were built. The relatively mature stoker boiler technology was improved by the introduction of water-cooled grates, staged combustion air, larger boiler sizes up to 60 MW, higher steam conditions, and advanced sootblowing systems. Circulating fluidized-bed (CFB) technology achieved full commercial status, and now is the leading process for most utility-scale power applications, with more complete combustion, lower emissions, and better fuel flexibility than stoker technology. Bubbling fluidized-bed (BFB) technology has an important market niche as the best process for difficult fuels such as agricultural wastes, typically in smaller plants. Other biomass powergeneration technologies are being developed for possible commercial introduction in the 1990s. Key components of Whole Tree Energy{trademark} technology have been tested, conceptual design studies have been completed with favorable results, and plans are being made for the first integrated process demonstration. Fluidized-bed gasification processes have advanced from pilot to demonstration status, and the world`s first integrated wood gasification/combined cycle utility power plant is starting operation in Sweden in early 1993. Several European vendors offer biomass gasification processes commercially. US electric utilities are evaluating the cofiring of biomass with fossil fuels in both existing and new plants. Retrofitting existing coal-fired plants gives better overall cost and performance results than any biomass technologies;but retrofit cofiring is {open_quotes}fuel-switching{close_quotes} that provides no new capacity and is attractive only with economic incentives.

A circuit-based technique enhances the power output of electrostatic generators employing an array of axially oriented rods or tubes or azimuthal corrugated metal surfaces for their electrodes. During generator operation, the peak voltage across the electrodes occurs at an azimuthal position that is intermediate between the position of minimum gap and maximum gap. If this position is also close to the azimuthal angle where the rate of change of capacity is a maximum, then the highest rf power output possible for a given maximum allowable voltage at the minimum gap can be attained. This rf power output is then coupled to the generator load through a coupling condenser that prevents suppression of the dc charging potential by conduction through the load. Optimized circuit values produce phase shifts in the rf output voltage that allow higher power output to occur at the same voltage limit at the minimum gap position.

Full Text Available This paper represents a novel modeling technique of PV module with a fuzzy logic based MPPT algorithm and boost converter in Simulink environment. The prime contributions of this work are simplification of PV modeling technique and implementation of fuzzy based MPPT system to track maximumpower efficiently. The main highlighted points of this paper are to demonstrate the precise control of the duty cycle with respect to various atmospheric conditions, illustration of PV characteristic curves, and operation analysis of the converter. The proposed system has been applied for three different PV modules SOLKAR 36 W, BP MSX 60 W, and KC85T 87 W. Finally the resultant data has been compared with the theoretical prediction and company specified value to ensure the validity of the system.

Full Text Available The Algerian government relies on a strategy focused on the development of inexhaustible resources such as solar and uses to diversify energy sources and prepare the Algeria of tomorrow: about 40% of the production of electricity for domestic consumption will be from renewable sources by 2030, Therefore it is necessary to concentrate our forces in order to reduce the application costs and to increment their performances, Their performance is evaluated and compared through theoretical analysis and digital simulation. This paper presents simulation of improved incremental conductance method for maximumpower point tracking (MPPT using DC-DC cuk converter. This improved algorithm is used to track MPPs because it performs precise control under rapidly changing Atmospheric conditions, Matlab/ Simulink were employed for simulation studies.

production of PV sources, despite the stochastically varying solar irradiation and ambient temperature conditions. Thereby, the overall efficiency of the PV energy production system is increased. Numerous techniques have been presented during the last decades for implementing the MPPT process in a PV system......A substantial growth of the installed photovoltaic (PV) systems capacity has occurred around the world during the last decade, thus enhancing the availability of electric energy in an environmentally friendly way. The maximumpower point tracking (MPPT) technique enables to maximize the energy....... This chapter provides an overview of the operating principles of these techniques, which are suited for either uniform or nonuniform solar irradiation conditions. The operational characteristics and implementation requirements of these MPPT methods are also analyzed in order to demonstrate their performance...

Highlights: • Thermoelectric generator was used and simulated within a salinity-gradient solar pond power plant. • Results showed that the thermoelectric generator can be able to enhance the power plant efficiency. • Results showed that the presented models can be able to produce generation even in the cold months. • The optimum size of area of solar pond based on its effect on efficiency is 50,000 m 2 . - Abstract: Salinity-gradient solar pond (SGSP) has been a reliable supply of heat source for powergeneration when it has been integrated with low temperature thermodynamics cycles like organic Rankine cycle (ORC). Also, thermoelectric generator (TEG) plays a critical role in the production of electricity from renewable energy sources. This paper investigates the potential of thermoelectric generator as a powergeneration system using heat from SGSP. In this work, thermoelectric generator was used instead of condenser of ORC with the purpose of improving the performance of system. Two new models of SGSP have been presented as: (1) SGSP using TEG in condenser of ORC without heat exchanger and (2) SGSP using TEG in condenser of ORC with heat exchanger. These proposed systems was evaluated through computer simulations. The ambient conditions were collected from beach of Urmia lake in IRAN. Simulation results indicated that, for identical conditions, the model 1 has higher performance than other model 2. For models 1 and 2 in T LCZ = 90 °C, the overall thermal efficiency of the solar pond power plant, were obtained 0.21% and 0.2% more than ORC without TEG, respectively.

MHD powergeneration can obtain electric energy directly from the heat energy of high speed plasma flow, and the powergenerating plant of 1 million kW can be realized by this method. When the MHD powergeneration method is combined before conventional thermal powergeneration method, the thermal efficiency can be raised to about 60% as compared with 38% in thermal powergeneration plants. The research and development of MHD powergeneration are in progress in USA and USSR. The research and development in Japan are in the second stage now after the first stage project for 10 years, and the Mark 7 generator with 100 kW electric output for 200 hr continuous operation is under construction. The MHD powergeneration is divided into three types according to the conductive fluids used, namely combustion type for thermal powergeneration, unequilibrated type and liquid metal type for nuclear powergeneration. The principle of MHD powergeneration and the constitution of the plant are explained. In Japan, the Mark 2 generatorgenerated 1,180 kW for 1 min in 1971, and the Mark 3 generatorgenerated 1.9 kW continuously for 110 hr in 1967. The MHD generator with superconducting magnet succeeded in 1969 to generate 25 kW for 6 min. The second stage project aimes at collecting design data and obtaining operational experience for the construction of 10 MW class pilot plant, and the Mark 7 and 8 generators are planned. (Kako, I.)

Two-energy-component fusion reactors in which the suprathermal component (D) is produced by harmonic cyclotron ''runaway'' of resonant ions are considered. In one ideal case, the fast hydromagnetic wave at ω = 2ω/sub cD/ produces an energy distribution f(W) approximately constant (up to W/sub max/) that includes all deuterons, which then thermalize and react with the cold tritons. In another ideal case, f(W) approximately constant is maintained by the fast wave at ω = ω/sub cD/. If one neglects (1) direct rf input to the bulk-plasma electrons and tritons, and (2) the fact that many deuterons are not resonantly accelerated, then the maximum ideal power gain is about 0.85 Q/sub m/ in the first case and 1.05 Q/sub m/ in the second case, where Q/sub m/ is the maximum fusion gain in the beam-injection scheme (e.g., Q/sub m/ = 1.9 at T/sub e/ = 10 keV). Because of nonideal effects, the cyclotron runaway phenomenon may find its most practical use in the heating of 50:50 D--T plasmas to ignition. (auth)

The high density of energy furnished by thermal plasma is profited in a wide range of applications, such as those related with welding fusion, spray coating and at the present in waste destruction. The waste destruction by plasma is a very attractive process because the remaining products are formed by inert glassy grains and non-toxic gases. The main characteristics of thermal plasmas are presented in this work. Techniques based on power electronics are utilized to achieve a good performance in thermal plasma generation. This work shown the design and construction of three phase control system for electric supply of thermal plasma torch, with 250 kw of capacity, as a part of the project named 'Destruction of hazard wastes by thermal plasma' actually working in the Instituto Nacional de Investigaciones Nucleares (ININ). The characteristics of thermal plasma and its generation are treated in the first chapter. The A C controllers by thyristors applied in three phase arrays are described in the chapter II, talking into account the power transformer, rectifiers bank and aliasing coil. The chapter III is dedicated in the design of the trigger module which controls the plasma current by varying the trigger angle of the SCR's; the protection and isolating unit are also presented in this chapter. The results and conclusions are discussed in chapter IV. (Author)

Industrial plants continuously reject large amounts of thermal energy through warm liquid or gaseous effluents during normal operation. These energy losses contribute to an inflation of production costs and also threaten the environment. This paper investigates methods of recovering the residual low grade thermal energy and converting it into higher quality mechanical energy using the thermodynamic Rankine cycle principle. For the temperature range of the available thermal energy, water was shown to be a poor working fluid for the conversion system, thus several potential working fluids, including ammonia, synthetic refrigerants, and organic compounds have been considered as alternatives. A comparative analysis led to the identification of different performance evaluation criteria. For example, the water-based Rankine cycle and, to a lesser extent, the ammonia-based Rankine cycle proved to be interesting when the powergeneration potential per unit working fluid mass flow rate was considered. On the other hand, Rankine-like cycles using dry hydrocarbon working fluids proved much more interesting in terms of energy conversion efficiency, as well as in terms of the net mechanical powergeneration potential for a given heat source. All performance indicators were low at low temperatures, and improved as the primary heat source was available at higher temperatures. This paper also discusses the influence of various external and internal operating parameters, such as heat source and heat sink temperatures, turbine and pump isentropic efficiencies and the addition of an internal heat exchanger on the overall performance of the energy recovery and conversion system.

Most IEA countries are liberalizing their electricity markets, shifting the responsibility for financing new investment in powergeneration to private investors. No longer able to automatically pass on costs to consumers, and with future prices of electricity uncertain, investors face a much riskier environment for investment in electricity infrastructure. This report looks at how investors have responded to the need to internalize investment risk in powergeneration. While capital and total costs remain the parameters shaping investment choices, the value of technologies which can be installed quickly and operated flexibly is increasingly appreciated. Investors are also managing risk by greater use of contracting, by acquiring retail businesses, and through mergers with natural gas suppliers. While liberalization was supposed to limit government intervention in the electricity market, volatile electricity prices have put pressure on governments to intervene and limit such prices. This study looks at several cases of volatile prices in IEA countries' electricity markets, and finds that while market prices can be a sufficient incentive for new investment in peak capacity, government intervention into the market to limit prices may undermine such investment

The Professionals Association and Nuclear Activity of National Atomic Energy Commission (CNEA) are following with great interest the worldwide discussions on global heating and the role that nuclear power is going to play. The Association has an active presence, as part of the WONUC (recognized by the United Nations as a Non-Governmental Organization) in the COP4, which was held in Buenos Aires in November 1998. The environmental problems are closely related to human development, the way of power production, the techniques for industrial production and exploitation fields. CO 2 is the most important gas with hothouse effects, responsible of progressive climatic changes, as floods, desertification, increase of average global temperature, thermal expansion in seas and even polar casks melting and ice falls. The consequences that global heating will have on the life and economy of human society cannot be sufficiently emphasized, great economical impact, destruction of ecosystems, loss of great coast areas and complete disappearance of islands owing to water level rise. The increase of power retained in the atmosphere generates more violent hurricanes and storms. In this work, the topics presented in the former AATN Meeting is analyzed in detail and different technological options and perspectives to mitigate CO 2 emission, as well as economical-financial aspects, are explored. (author)

We report experimental and theoretical results on a ballistic energy-conversion method based on a rotary atomizer working with a droplet acceleration-deceleration cycle. In a rotary atomizer, liquid is fed onto the center of a rotating flat surface, where it spreads out under the action of the centrifugal force and creates "atomized" droplets at its edge. The advantage of using a rotary atomizer is that the centrifugal force exerted on the fluid on a smooth, large surface is not only a robust form of acceleration, as it avoids clogging, but also easily allows high throughput, and produces high electrical power. We successfully demonstrate an output power of 4.9 mW and a high voltage up to 3120 V. At present, the efficiency of the system is still low (0.14%). However, the conversion mechanism of the system is fully interpreted in this paper, permitting a conceptual understanding of system operation and providing a roadmap for system optimization. This observation will open up a road for building power-generation systems in the near future.

Full Text Available This work considers the nonlinear scattering theory for three-terminal thermoelectric devices used for powergeneration or refrigeration. Such systems are quantum phase-coherent versions of a thermocouple, and the theory applies to systems in which interactions can be treated at a mean-field level. It considers an arbitrary three-terminal system in any external magnetic field, including systems with broken time-reversal symmetry, such as chiral thermoelectrics, as well as systems in which the magnetic field plays no role. It is shown that the upper bound on efficiency at given power output is of quantum origin and is stricter than Carnot’s bound. The bound is exactly the same as previously found for two-terminal devices and can be achieved by three-terminal systems with or without broken time-reversal symmetry, i.e., chiral and non-chiral thermoelectrics.

The present study focused on how to improve the maximumpower output of a thermoelectric generator (TEG) system and move heat to any suitable space using a TEG associated with a loop thermosyphon (loop-type heat pipe). An experimental study was carried out to investigate the power output, the temperature difference of the thermoelectric module (TEM), and the heat transfer performance associated with the characteristic of the researched heat pipe. Currently, internal combustion engines lose more than 35% of their fuel energy as recyclable heat in the exhaust gas, but it is not easy to recycle waste heat using TEGs because of the limited space in vehicles. There are various advantages to use of TEGs over other power sources, such as the absence of moving parts, a long lifetime, and a compact system configuration. The present study presents a novel TEG concept to transfer heat from the heat source to the sink. This technology can transfer waste heat to any location. This simple and novel design for a TEG can be applied to future hybrid cars. The present TEG system with a heat pipe can transfer heat and generatepower of around 1.8 V with T TEM = 58°C. The heat transfer performance of a loop-type heat pipe with various working fluids was investigated, with water at high heat flux (90 W) and 0.05% TiO2 nanofluid at low heat flux (30 W to 70 W) showing the best performance in terms of powergeneration. The heat pipe can transfer the heat to any location where the TEM is installed.

This article presents a novel control strategy for a 1-ϕ 2-level grid-tie photovoltaic (PV) inverter to enhance the power quality (PQ) of a PV distributed generation (PVDG) system. The objective is to obtain the maximum benefits from the grid-tie PV inverter by introducing current harmonics as well as reactive power compensation schemes in its control strategy, thereby controlling the PV inverter to achieve multiple functions in the PVDG system such as: (1) active power flow control between the PV inverter and the grid, (2) reactive power compensation, and (3) grid current harmonics compensation. A PQ enhancement controller (PQEC) has been designed to achieve the aforementioned objectives. The issue of underutilisation of the PV inverter in nighttime has also been addressed in this article and for the optimal use of the system; the PV inverter is used as a shunt active power filter in nighttime. A prototype model of the proposed system is developed in the laboratory, to validate the effectiveness of the control scheme, and is tested with the help of the dSPACE DS1104 platform.

Full Text Available This work presents the design, modeling, and implementation of a neural network inverse model controller for tracking the maximumpower point of a photovoltaic (PV module. A nonlinear autoregressive network with exogenous inputs (NARX was implemented in a serial-parallel architecture. The PV module mathematical modeling was developed, a buck converter was designed to operate in the continuous conduction mode with a switching frequency of 20 KHz, and the dynamic neural controller was designed using the Neural Network Toolbox from Matlab/Simulink (MathWorks, Natick, MA, USA, and it was implemented on an open-hardware Arduino Mega board. To obtain the reference signals for the NARX and determine the 65 W PV module behavior, a system made of a 0.8 W PV cell, a temperature sensor, a voltage sensor and a static neural network, was used. To evaluate performance a comparison with the P&O traditional algorithm was done in terms of response time and oscillations around the operating point. Simulation results demonstrated the superiority of neural controller over the P&O. Implementation results showed that approximately the same power is obtained with both controllers, but the P&O controller presents oscillations between 7 W and 10 W, in contrast to the inverse controller, which had oscillations between 1 W and 2 W.

Full Text Available The maximumpower point tracker techniques vary in many aspects as simplicity, digital or analogical implementation, sensor required, convergence speed, range of effectiveness, implementation hardware,popularity, cost and in other aspects. This paper presents in details comparative study between two most popular algorithm technique which is incremental conductance algorithm and perturb and observe algorithm. Two different converters buck and cuk converter use for comparative in this study. Few comparisons such as efficiency, voltage, current and power output for each different combination have been recorded. Multi changes in irradiance, temperature by keeping voltage and current as main sensed parameter been done in the simulation. Matlab simulink tools have been used for performance evaluation on energy point. Simulation will consider different solar irradiance and temperature variations.

Direct detection of the Epoch of Reionization (EoR) via the red-shifted 21-cm line will have unprecedented implications on the study of structure formation in the infant Universe. To fulfil this promise, current and future 21-cm experiments need to detect this weak EoR signal in the presence of foregrounds that are several orders of magnitude larger. This requires extreme noise control and improved wide-field high dynamic-range imaging techniques. We propose a new imaging method based on a maximum likelihood framework which solves for the interferometric equation directly on the sphere, or equivalently in the uvw-domain. The method uses the one-to-one relation between spherical waves and spherical harmonics (SpH). It consistently handles signals from the entire sky, and does not require a w-term correction. The SpH coefficients represent the sky-brightness distribution and the visibilities in the uvw-domain, and provide a direct estimate of the spatial power spectrum. Using these spectrally smooth SpH coefficients, bright foregrounds can be removed from the signal, including their side-lobe noise, which is one of the limiting factors in high dynamics-range wide-field imaging. Chromatic effects causing the so-called `wedge' are effectively eliminated (i.e. deconvolved) in the cylindrical (k⊥, k∥) power spectrum, compared to a power spectrum computed directly from the images of the foreground visibilities where the wedge is clearly present. We illustrate our method using simulated Low-Frequency Array observations, finding an excellent reconstruction of the input EoR signal with minimal bias.

The main results of a theoretical work on the use of a low temperature heat source for powergeneration through a carbon dioxide transcritical power cycle are reported in this paper. The procedure for analyzing the behaviour of the proposed cycle consisted in modifying the input pressure to the turbine from 66 bar, maintained constant each evaluated temperature (60 o C, 90 o C, 120 o C and 150 o C) until the net work was approximately zero. As a result, the maximum exergy efficiency was 50%, while the energy efficiencies obtained were 9.8%, 7.3%, 4.9% and 2.4% and the net specific work was 18.2 kJ/kg, 12.8 kJ/kg, 7.8 kJ/kg and 3.5 kJ/kg, respectively. Furthermore, the effect of the addition of an internal heat exchanger, which obviously supposed an increase in the efficiency, was analyzed. The analysis of the proposed system shows the viability of implementing this type of process as an energy alternative and/or strengthener of non-conventional energy sources in non-provided zones, or for increasing the energy efficiency in the industry. -- Highlights: → Energy and exergy analysis of a carbon dioxide transcritical power cycle is reported. → The effect of the inlet temperature to the turbine is evaluated. → Conditions of maximum efficiency and maximum net work are compared. → The inclusion of an IHX is also analysed.

Photovoltaic (PV) energy is one of the most important energy resources since it is clean, pollution free, and endless. MaximumPower Point Tracking (MPPT) is used in photovoltaic (PV) systems to maximize the photovoltaic output power, irrespective the variations of temperature and radiation conditions. This paper presents a comparison between Ćuk and SEPIC converter in maximumpower point tracking (MPPT) of photovoltaic (PV) system. In the paper, advantages and disadvantages of both converter...

Full Text Available A short overview of different piezoelectric structures and devices for generating renewable electricity under mechanical actions is presented. A vibrating piezoelectric device differs from a typical electrical power source in that it has capacitive rather than inductive source impedance, and may be driven by mechanical vibrations of varying amplitude. Several techniques have been developed to extract energy from the environment. Generally, “vibration energy” could be converted into electrical energy by three techniques: electrostatic charge, magnetic fields and piezoelectric. Mechanical resonance frequency of piezoelectric bimorph transducers depends on geometric size (length, width, and thickness of each layer, and the piezoelectric coefficients of the piezoelectric material. Manufacturing processes and intended applications of several energy harvesting devices are presented.

A 150 Watt thermophotovoltaic (TPV) powergenerator is being developed. The technical approach taken in the design focused on optimizing the integrated performance of the primary subsystems in order to yield high energy conversion efficiency and cost effectiveness. An important aspect of the approach is the use of a selective emitter radiating to a bandgap matched photovoltaic array to minimize thermal and optical recuperation requirements, as well as the non-recoverable heat losses. For the initial prototype system, fibrous ytterbia emitters radiating in a band centered at 980 nm are matched with high efficiency silicon photoconverters. The integrated system includes a dielectric stack filter for optical energy recovery and a ceramic recuperator for thermal energy recovery. The system has been operated with air preheat temperatures up to 1350K. The design of the system and development status are presented.

As the Hitachi Group's efforts in nuclear powergeneration, this paper explains the safety improvement technologies that are currently under development or promotion. As efforts for the decommissioning of Fukushima Daiichi Nuclear Power Station, the following items have been developed. (1) As for the spent fuel removal of Unit 4, the following items have mainly been conducted: removal of the debris piled up on the top surface of existing reactor building (R/B), removal of the debris deposited in spent fuel pool (SFP), and fuel transfer operation by means of remote underwater work. The removal of all spent fuels was completed in 2014. (2) The survey robots inside R/B, which are composed of a basement survey robot to check leaking spots at upper pressure suppression chamber and a floor running robot to check leaking spots in water, were verified with a field demonstration test at Unit 1. These robots were able to find the leaking spots at midair pipe expansion joint. (3) As the survey robot for reactor containment shells, robots of I-letter posture and horizontal U-letter posture were developed, and the survey on the upper part of first-floor grating inside the containment shells was performed. (4) As the facilities for contaminated water measures, sub-drain purification equipment, Advanced Liquid Processing System, etc. were developed and supplied, which are now showing good performance. On the other hand, an advanced boiling water reactor with high safety of the United Kingdom (UK ABWR) is under procedure of approval for introduction. In addition, a next-generation light-water reactor of transuranic element combustion type is under development. (A.O.)

The thermoelectric generation (TEG) system has its special charactristics of high stablility, low voltage and high current output, which is different from PV modules. The power conditioning system and control schemes used in PV applications cannot be directly applied to TEG applications. A power...... conditioning system for TEG based on interleaved Boost converter with maximumpower point tracking (MPPT) control is investigated in this paper. Since an internal resistance exists inside TEG modules, an improved perturbation and observation (P&O) MPPT control scheme with power limit is proposed to extract...... maximumpower from TEG by matching the load with internal resistance. Since the battery is usually employed as the load for TEG systems, the interleaved Boost converter operates in two different modes for battery charging: before the battery is fully charged, the system outputs the maximumpower (MPPT...